Identify unused, never read, and never written vars

19 files changed, 112 insertions, 110 deletions

diff --git a/data/event_scripts.s b/data/event_scripts.s
index 19b4949eb..abc60dd18 100644
--- a/data/event_scripts.s
+++ b/data/event_scripts.s
@@ -3193,7 +3193,7 @@ UnusualWeather_EventScript_EndEventAndCleanup_2:: @ 8273D31
 	call UnusualWeather_EventScript_CleanupMapTiles
 	special DrawWholeMapView
 	setvar VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_NONE
-	setvar VAR_0x4039, 0
+	setvar VAR_SHOULD_END_UNUSUAL_WEATHER, 0
 	clearflag FLAG_SPECIAL_FLAG_0x4000
 	fadescreenswapbuffers 0
 	releaseall
diff --git a/data/maps/FarawayIsland_Interior/scripts.inc b/data/maps/FarawayIsland_Interior/scripts.inc
index 7051d376c..bee33ae07 100644
--- a/data/maps/FarawayIsland_Interior/scripts.inc
+++ b/data/maps/FarawayIsland_Interior/scripts.inc
@@ -38,7 +38,7 @@ FarawayIsland_Interior_EventScript_267D5E:: @ 8267D5E
 	return
 
 FarawayIsland_Interior_MapScript1_267D72: @ 8267D72
-	setvar VAR_0x403A, 0
+	setvar VAR_NEVER_READ_0x403A, 0
 	setvar VAR_TEMP_1, 1
 	call_if_unset FLAG_CAUGHT_MEW, FarawayIsland_Interior_EventScript_267D86
 	end
diff --git a/data/maps/MarineCave_End/scripts.inc b/data/maps/MarineCave_End/scripts.inc
index 036fa7724..028075648 100644
--- a/data/maps/MarineCave_End/scripts.inc
+++ b/data/maps/MarineCave_End/scripts.inc
@@ -47,13 +47,13 @@ MarineCave_End_EventScript_23B01B:: @ 823B01B
 	goto_if_eq MarineCave_End_EventScript_23B092
 	compare VAR_RESULT, 5
 	goto_if_eq MarineCave_End_EventScript_23B092
-	setvar VAR_0x4039, 1
+	setvar VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	setflag FLAG_DEFEATED_KYOGRE
 	releaseall
 	end
 
 MarineCave_End_EventScript_23B084:: @ 823B084
-	setvar VAR_0x4039, 1
+	setvar VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	setflag FLAG_DEFEATED_KYOGRE
 	goto MarineCave_End_EventScript_27376D
 	end
diff --git a/data/maps/PetalburgCity_Gym/scripts.inc b/data/maps/PetalburgCity_Gym/scripts.inc
index 1f0fdd91c..fef5c4048 100644
--- a/data/maps/PetalburgCity_Gym/scripts.inc
+++ b/data/maps/PetalburgCity_Gym/scripts.inc
@@ -60,7 +60,7 @@ PetalburgCity_Gym_EventScript_204955:: @ 8204955
 	return
 
 PetalburgCity_Gym_EventScript_20495D:: @ 820495D
-	setorcopyvar VAR_0x8015, 269
+	setorcopyvar VAR_NEVER_READ_0x8015, 269
 	specialvar VAR_RESULT, IsTrainerReadyForRematch
 	compare VAR_RESULT, 1
 	goto_if_eq PetalburgCity_Gym_EventScript_204985
diff --git a/data/maps/Route105/scripts.inc b/data/maps/Route105/scripts.inc
index 1f4202ec4..2b8ebe305 100644
--- a/data/maps/Route105/scripts.inc
+++ b/data/maps/Route105/scripts.inc
@@ -18,7 +18,7 @@ Route105_EventScript_1EE20B:: @ 81EE20B
 	return
 
 Route105_MapScript1_1EE21E: @ 81EE21E
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route105_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_105_NORTH
 	call_if_eq UnusualWeather_StartKyogreWeather
@@ -27,7 +27,7 @@ Route105_MapScript1_1EE21E: @ 81EE21E
 	end
 
 Route105_MapScript2_1EE240: @ 81EE240
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route105_EventScript_1EE24A:: @ 81EE24A
diff --git a/data/maps/Route114/scripts.inc b/data/maps/Route114/scripts.inc
index 6a2f8b174..b03a2f228 100644
--- a/data/maps/Route114/scripts.inc
+++ b/data/maps/Route114/scripts.inc
@@ -5,7 +5,7 @@ Route114_MapScripts:: @ 81F252F
 	.byte 0
 
 Route114_MapScript1_1F253F: @ 81F253F
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route114_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_114_NORTH
 	call_if_eq UnusualWeather_StartGroudonWeather
@@ -21,7 +21,7 @@ Route114_MapScript1_1F2561: @ 81F2561
 	end
 
 Route114_MapScript2_1F2578: @ 81F2578
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route114_EventScript_1F2582:: @ 81F2582
diff --git a/data/maps/Route115/scripts.inc b/data/maps/Route115/scripts.inc
index be3a98f42..259cd5904 100644
--- a/data/maps/Route115/scripts.inc
+++ b/data/maps/Route115/scripts.inc
@@ -12,7 +12,7 @@ Route115_MapScript1_1F2930: @ 81F2930
 	end
 
 Route115_MapScript1_1F2947: @ 81F2947
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route115_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_115_WEST
 	call_if_eq UnusualWeather_StartGroudonWeather
@@ -21,7 +21,7 @@ Route115_MapScript1_1F2947: @ 81F2947
 	end
 
 Route115_MapScript2_1F2969: @ 81F2969
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route115_EventScript_1F2973:: @ 81F2973
diff --git a/data/maps/Route116/scripts.inc b/data/maps/Route116/scripts.inc
index 193b70157..454201307 100644
--- a/data/maps/Route116/scripts.inc
+++ b/data/maps/Route116/scripts.inc
@@ -6,7 +6,7 @@ Route116_MapScripts:: @ 81F2C0C
 
 Route116_MapScript1_1F2C1C: @ 81F2C1C
 	call_if_set FLAG_RECOVERED_DEVON_GOODS, Route116_EventScript_1F2C47
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route116_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_116_NORTH
 	call_if_eq UnusualWeather_StartGroudonWeather
@@ -26,7 +26,7 @@ Route116_MapScript1_1F2C4F: @ 81F2C4F
 	end
 
 Route116_MapScript2_1F2C66: @ 81F2C66
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route116_EventScript_1F2C70:: @ 81F2C70
diff --git a/data/maps/Route118/scripts.inc b/data/maps/Route118/scripts.inc
index a2784b298..9c1ec46ca 100644
--- a/data/maps/Route118/scripts.inc
+++ b/data/maps/Route118/scripts.inc
@@ -6,7 +6,7 @@ Route118_MapScripts:: @ 81F3DBC
 
 Route118_MapScript1_1F3DCC: @ 81F3DCC
 	call Route118_EventScript_28CCC7
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route118_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_118_EAST
 	call_if_eq UnusualWeather_StartGroudonWeather
@@ -22,7 +22,7 @@ Route118_MapScript1_1F3DF3: @ 81F3DF3
 	end
 
 Route118_MapScript2_1F3E0A: @ 81F3E0A
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route118_EventScript_1F3E14:: @ 81F3E14
diff --git a/data/maps/Route125/scripts.inc b/data/maps/Route125/scripts.inc
index a2e9f1d40..8abcbe787 100644
--- a/data/maps/Route125/scripts.inc
+++ b/data/maps/Route125/scripts.inc
@@ -6,7 +6,7 @@ Route125_MapScripts:: @ 81F6748
 
 Route125_MapScript1_1F6758: @ 81F6758
 	call_if_set FLAG_SYS_WEATHER_CTRL, Common_EventScript_SetWeather15
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route125_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_125_WEST
 	call_if_eq UnusualWeather_StartKyogreWeather
@@ -22,7 +22,7 @@ Route125_MapScript1_1F6783: @ 81F6783
 	end
 
 Route125_MapScript2_1F679A: @ 81F679A
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route125_EventScript_1F67A4:: @ 81F67A4
diff --git a/data/maps/Route127/scripts.inc b/data/maps/Route127/scripts.inc
index 27b17d340..91fab2b61 100644
--- a/data/maps/Route127/scripts.inc
+++ b/data/maps/Route127/scripts.inc
@@ -6,7 +6,7 @@ Route127_MapScripts:: @ 81F69D9
 
 Route127_MapScript1_1F69E9: @ 81F69E9
 	call_if_set FLAG_SYS_WEATHER_CTRL, Common_EventScript_SetWeather15
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route127_EventScript_273D13
 	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_127_NORTH
 	call_if_eq UnusualWeather_StartKyogreWeather
@@ -22,7 +22,7 @@ Route127_MapScript1_1F6A14: @ 81F6A14
 	end
 
 Route127_MapScript2_1F6A2B: @ 81F6A2B
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route127_EventScript_1F6A35:: @ 81F6A35
diff --git a/data/maps/Route129/scripts.inc b/data/maps/Route129/scripts.inc
index 3fc30cf91..0cd5f838a 100644
--- a/data/maps/Route129/scripts.inc
+++ b/data/maps/Route129/scripts.inc
@@ -12,7 +12,7 @@ Route129_MapScript1_1F7294: @ 81F7294
 	end
 
 Route129_MapScript1_1F72AB: @ 81F72AB
-	compare VAR_0x4039, 1
+	compare VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	call_if_eq Route129_EventScript_273D13
 	compare VAR_0x405E, 4
 	call_if_ge Route129_EventScript_1F72D8
@@ -27,7 +27,7 @@ Route129_EventScript_1F72D8:: @ 81F72D8
 	return
 
 Route129_MapScript2_1F72E2: @ 81F72E2
-	map_script_2 VAR_0x4039, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
+	map_script_2 VAR_SHOULD_END_UNUSUAL_WEATHER, 1, UnusualWeather_EventScript_EndEventAndCleanup_1
 	.2byte 0
 
 Route129_EventScript_1F72EC:: @ 81F72EC
diff --git a/data/maps/TerraCave_End/scripts.inc b/data/maps/TerraCave_End/scripts.inc
index 3f892315d..b5a664a76 100644
--- a/data/maps/TerraCave_End/scripts.inc
+++ b/data/maps/TerraCave_End/scripts.inc
@@ -47,13 +47,13 @@ TerraCave_End_EventScript_23B0EC:: @ 823B0EC
 	goto_if_eq TerraCave_End_EventScript_23B163
 	compare VAR_RESULT, 5
 	goto_if_eq TerraCave_End_EventScript_23B163
-	setvar VAR_0x4039, 1
+	setvar VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	setflag FLAG_DEFEATED_GROUDON
 	releaseall
 	end
 
 TerraCave_End_EventScript_23B155:: @ 823B155
-	setvar VAR_0x4039, 1
+	setvar VAR_SHOULD_END_UNUSUAL_WEATHER, 1
 	setflag FLAG_DEFEATED_GROUDON
 	goto TerraCave_End_EventScript_27376D
 	end
diff --git a/include/constants/vars.h b/include/constants/vars.h
index 9f364416c..1ca36b8ad 100644
--- a/include/constants/vars.h
+++ b/include/constants/vars.h
@@ -71,10 +71,10 @@
 #define VAR_DEOXYS_ROCK_STEP_COUNT           0x4034
 #define VAR_DEOXYS_ROCK_LEVEL                0x4035
 #define VAR_STORAGE_UNKNOWN                  0x4036
-#define VAR_UNUSUAL_WEATHER_LOCATION                           0x4037
-#define VAR_0x4038                           0x4038
-#define VAR_0x4039                           0x4039
-#define VAR_0x403A                           0x403A
+#define VAR_UNUSUAL_WEATHER_LOCATION         0x4037
+#define VAR_UNUSUAL_WEATHER_STEP_COUNTER     0x4038
+#define VAR_SHOULD_END_UNUSUAL_WEATHER       0x4039
+#define VAR_NEVER_READ_0x403A                0x403A // Var is written to, but never checked
 #define VAR_REGICE_STEPS_1                   0x403B
 #define VAR_REGICE_STEPS_2                   0x403C
 #define VAR_REGICE_STEPS_3                   0x403D
@@ -94,60 +94,60 @@
 #define VAR_POKELOT_RND1                     0x404B
 #define VAR_POKELOT_RND2                     0x404C
 #define VAR_0x404D                           0x404D
-#define VAR_0x404E                           0x404E
+#define VAR_UNUSED_0x404E                    0x404E // Unused Var
 #define VAR_LOTAD_SIZE_RECORD                0x404F
 #define VAR_0x4050                           0x4050
 #define VAR_ROUTE102_ACCESSIBLE              0x4051
-#define VAR_0x4052                           0x4052
+#define VAR_UNUSED_0x4052                    0x4052 // Unused Var
 #define VAR_LAVARIDGE_RIVAL_STATE            0x4053
 #define VAR_CURRENT_SECRET_BASE              0x4054
-#define VAR_0x4055                           0x4055
-#define VAR_0x4056                           0x4056
+#define VAR_UNUSED_0x4055                    0x4055 // Unused Var
+#define VAR_UNUSED_0x4056                    0x4056 // Unused Var
 #define VAR_PETALBURG_STATE                  0x4057
 #define VAR_SLATEPORT_STATE                  0x4058
-#define VAR_0x4059                           0x4059
+#define VAR_UNUSED_0x4059                    0x4059 // Unused Var
 #define VAR_RUSTBORO_STATE                   0x405A
-#define VAR_0x405B                           0x405B
-#define VAR_0x405C                           0x405C
+#define VAR_UNUSED_0x405B                    0x405B // Unused Var
+#define VAR_UNUSED_0x405C                    0x405C // Unused Var
 #define VAR_0x405D                           0x405D
 #define VAR_0x405E                           0x405E
-#define VAR_0x405F                           0x405F
+#define VAR_UNUSED_0x405F                    0x405F // Unused Var
 #define VAR_ROUTE101_STATE                   0x4060
-#define VAR_0x4061                           0x4061
-#define VAR_0x4062                           0x4062
+#define VAR_UNUSED_0x4061                    0x4061 // Unused Var
+#define VAR_UNUSED_0x4062                    0x4062 // Unused Var
 #define VAR_0x4063                           0x4063
-#define VAR_0x4064                           0x4064
-#define VAR_0x4065                           0x4065
-#define VAR_0x4066                           0x4066
-#define VAR_0x4067                           0x4067
-#define VAR_0x4068                           0x4068
+#define VAR_UNUSED_0x4064                    0x4064 // Unused Var
+#define VAR_UNUSED_0x4065                    0x4065 // Unused Var
+#define VAR_UNUSED_0x4066                    0x4066 // Unused Var
+#define VAR_UNUSED_0x4067                    0x4067 // Unused Var
+#define VAR_UNUSED_0x4068                    0x4068 // Unused Var
 #define VAR_ROUTE110_STATE                   0x4069
-#define VAR_0x406A                           0x406A
-#define VAR_0x406B                           0x406B
-#define VAR_0x406C                           0x406C
-#define VAR_0x406D                           0x406D
-#define VAR_0x406E                           0x406E
+#define VAR_UNUSED_0x406A                    0x406A // Unused Var
+#define VAR_UNUSED_0x406B                    0x406B // Unused Var
+#define VAR_UNUSED_0x406C                    0x406C // Unused Var
+#define VAR_UNUSED_0x406D                    0x406D // Unused Var
+#define VAR_UNUSED_0x406E                    0x406E // Unused Var
 #define VAR_ROUTE116_STATE                   0x406F
-#define VAR_0x4070                           0x4070
+#define VAR_UNUSED_0x4070                    0x4070 // Unused Var
 #define VAR_ROUTE118_STATE                   0x4071
 #define VAR_ROUTE119_STATE                   0x4072
-#define VAR_0x4073                           0x4073
+#define VAR_UNUSED_0x4073                    0x4073 // Unused Var
 #define VAR_ROUTE121_STATE                   0x4074
-#define VAR_0x4075                           0x4075
-#define VAR_0x4076                           0x4076
-#define VAR_0x4077                           0x4077
-#define VAR_0x4078                           0x4078
-#define VAR_0x4079                           0x4079
-#define VAR_0x407A                           0x407A
+#define VAR_UNUSED_0x4075                    0x4075 // Unused Var
+#define VAR_UNUSED_0x4076                    0x4076 // Unused Var
+#define VAR_UNUSED_0x4077                    0x4077 // Unused Var
+#define VAR_UNUSED_0x4078                    0x4078 // Unused Var
+#define VAR_UNUSED_0x4079                    0x4079 // Unused Var
+#define VAR_UNUSED_0x407A                    0x407A // Unused Var
 #define VAR_ROUTE128_STATE                   0x407B
-#define VAR_0x407C                           0x407C
-#define VAR_0x407D                           0x407D
-#define VAR_0x407E                           0x407E
-#define VAR_0x407F                           0x407F
-#define VAR_0x4080                           0x4080
-#define VAR_0x4081                           0x4081
+#define VAR_UNUSED_0x407C                    0x407C // Unused Var
+#define VAR_UNUSED_0x407D                    0x407D // Unused Var
+#define VAR_UNUSED_0x407E                    0x407E // Unused Var
+#define VAR_UNUSED_0x407F                    0x407F // Unused Var
+#define VAR_UNUSED_0x4080                    0x4080 // Unused Var
+#define VAR_UNUSED_0x4081                    0x4081 // Unused Var
 #define VAR_LITTLEROOT_HOUSES_STATE          0x4082
-#define VAR_0x4083                           0x4083
+#define VAR_UNUSED_0x4083                    0x4083 // Unused Var
 #define VAR_BIRCH_LAB_STATE                  0x4084
 #define VAR_PETALBURG_GYM_STATE              0x4085
 #define VAR_LINK_CONTEST_ROOM_STATE          0x4086
@@ -155,13 +155,13 @@
 #define VAR_CONTEST_LOCATION                 0x4088
 #define VAR_0x4089                           0x4089
 #define VAR_CONTEST_PRIZE_PICKUP             0x408A
-#define VAR_0x408B                           0x408B
+#define VAR_UNUSED_0x408B                    0x408B // Unused Var
 #define VAR_LITTLEROOT_HOUSES_STATE_2        0x408C
 #define VAR_LITTLEROOT_RIVAL_STATE           0x408D
 #define VAR_BOARD_BRINEY_BOAT_ROUTE104_STATE 0x408E
 #define VAR_DEVON_CORP_3F_STATE              0x408F
 #define VAR_BRINEY_HOUSE_STATE               0x4090
-#define VAR_0x4091                           0x4091
+#define VAR_UNUSED_0x4091                    0x4091 // Unused Var
 #define VAR_LITTLEROOT_INTRO_STATE           0x4092
 #define VAR_MAUVILLE_GYM_STATE               0x4093
 #define VAR_LILYCOVE_MUSEUM_2F_STATE         0x4094
@@ -171,20 +171,20 @@
 #define VAR_PETALBURG_WOODS_STATE            0x4098
 #define VAR_LILYCOVE_CONTEST_LOBBY_STATE     0x4099
 #define VAR_RUSTURF_TUNNEL_STATE             0x409A
-#define VAR_0x409B                           0x409B
+#define VAR_UNUSED_0x409B                    0x409B // Unused Var
 #define VAR_ELITE_4_STATE                    0x409C
-#define VAR_0x409D                           0x409D
+#define VAR_UNUSED_0x409D                    0x409D // Unused Var
 #define VAR_0x409E                           0x409E
 #define VAR_0x409F                           0x409F
 #define VAR_SLATEPORT_HARBOR_STATE           0x40A0
-#define VAR_0x40A1                           0x40A1
+#define VAR_UNUSED_0x40A1                    0x40A1 // Unused var
 #define VAR_SEAFLOOR_CAVERN_STATE            0x40A2
 #define VAR_CABLE_CAR_STATION_STATE          0x40A3
 #define VAR_SAFARI_ZONE_STATE                0x40A4
 #define VAR_TRICK_HOUSE_ENTRANCE_STATE_1     0x40A5
 #define VAR_TRICK_HOUSE_ENTRANCE_STATE_2     0x40A6
 #define VAR_TRICK_HOUSE_ENTRANCE_STATE_3     0x40A7
-#define VAR_0x40A8                           0x40A8
+#define VAR_UNUSED_0x40A8                    0x40A8 // Unused Var
 #define VAR_CYCLING_CHALLENGE_STATE          0x40A9
 #define VAR_SLATEPORT_MUSEUM_1F_STATE        0x40AA
 #define VAR_TRICK_HOUSE_PUZZLE_1_STATE       0x40AB
@@ -197,13 +197,13 @@
 #define VAR_TRICK_HOUSE_PUZZLE_8_STATE       0x40B2
 #define VAR_WEATHER_INSTITUTE_STATE          0x40B3
 #define VAR_PORTHOLE_STATE                   0x40B4
-#define VAR_TRICK_HOUSE_STATE                0x40B5  // TODO: needs some further investigation
+#define VAR_TRICK_HOUSE_STATE                0x40B5 // TODO: needs some further investigation
 #define VAR_TRICK_HOUSE_PUZZLE_7_STATE_2     0x40B6
 #define VAR_SLATEPORT_FAN_CLUB_STATE         0x40B7
-#define VAR_0x40B8                           0x40B8
+#define VAR_UNUSED_0x40B8                    0x40B8 // Unused Var
 #define VAR_MT_PYRE_STATE                    0x40B9
 #define VAR_NEW_MAUVILLE_STATE               0x40BA
-#define VAR_0x40BB                           0x40BB
+#define VAR_UNUSED_0x40BB                    0x40BB // Unused Var
 #define VAR_BRAVO_TRAINER_BATTLE_TOWER_ON    0x40BC
 #define VAR_JAGGED_PASS_ASH_WEATHER          0x40BD
 #define VAR_GLASS_WORKSHOP_STATE             0x40BE
@@ -235,17 +235,17 @@
 #define VAR_0x40D8                           0x40D8
 #define VAR_0x40D9                           0x40D9
 #define VAR_0x40DA                           0x40DA
-#define VAR_0x40DB                           0x40DB
-#define VAR_0x40DC                           0x40DC
+#define VAR_UNUSED_0x40DB                    0x40DB // Unused Var
+#define VAR_UNUSED_0x40DC                    0x40DC // Unused Var
 #define VAR_EVENT_PICHU_SLOT                 0x40DD
-#define VAR_0x40DE                           0x40DE
-#define VAR_0x40DF                           0x40DF
-#define VAR_0x40E0                           0x40E0
-#define VAR_0x40E1                           0x40E1
-#define VAR_0x40E2                           0x40E2
-#define VAR_0x40E3                           0x40E3
-#define VAR_0x40E4                           0x40E4
-#define VAR_0x40E5                           0x40E5
+#define VAR_NEVER_READ_0x40DE                0x40DE // Var is written to, but never read
+#define VAR_NEVER_READ_0x40DF                0x40DF // Var is written to, but never read
+#define VAR_NEVER_READ_0x40E0                0x40E0 // Var is written to, but never read
+#define VAR_NEVER_READ_0x40E1                0x40E1 // Var is written to, but never read
+#define VAR_NEVER_READ_0x40E2                0x40E2 // Var is written to, but never read
+#define VAR_NEVER_READ_0x40E3                0x40E3 // Var is written to, but never read
+#define VAR_NEVER_READ_0x40E4                0x40E4 // var is written to, but never read
+#define VAR_UNUSED_0x40E5                    0x40E5 // Unused Var
 #define VAR_DAILY_SLOTS                      0x40E6
 #define VAR_DAILY_WILDS                      0x40E7
 #define VAR_DAILY_BLENDER                    0x40E8
@@ -263,15 +263,15 @@
 #define VAR_0x40F4                           0x40F4
 #define VAR_0x40F5                           0x40F5
 #define VAR_0x40F6                           0x40F6
-#define VAR_0x40F7                           0x40F7
-#define VAR_0x40F8                           0x40F8
-#define VAR_0x40F9                           0x40F9
-#define VAR_0x40FA                           0x40FA
-#define VAR_0x40FB                           0x40FB
-#define VAR_0x40FC                           0x40FC
-#define VAR_0x40FD                           0x40FD
-#define VAR_0x40FE                           0x40FE
-#define VAR_0x40FF                           0x40FF
+#define VAR_UNUSED_0x40F7                    0x40F7 // Unused Var
+#define VAR_UNUSED_0x40F8                    0x40F8 // Unused Var
+#define VAR_UNUSED_0x40F9                    0x40F9 // Unused Var
+#define VAR_UNUSED_0x40FA                    0x40FA // Unused Var
+#define VAR_UNUSED_0x40FB                    0x40FB // Unused Var
+#define VAR_UNUSED_0x40FC                    0x40FC // Unused Var
+#define VAR_UNUSED_0x40FD                    0x40FD // Unused Var
+#define VAR_UNUSED_0x40FE                    0x40FE // Unused Var
+#define VAR_UNUSED_0x40FF                    0x40FF // Unused Var
 
 #define SPECIAL_VARS_START 0x8000
 // special vars
@@ -297,6 +297,6 @@
 #define VAR_MON_BOX_ID             0x8012
 #define VAR_MON_BOX_POS            0x8013
 #define VAR_0x8014                 0x8014
-#define VAR_0x8015                 0x8015
+#define VAR_NEVER_READ_0x8015      0x8015 // Written to, but never read
 
 #endif // GUARD_CONSTANTS_VARS_H
diff --git a/include/field_specials.h b/include/field_specials.h
index bff04a739..1ab2b7eb4 100644
--- a/include/field_specials.h
+++ b/include/field_specials.h
@@ -7,7 +7,7 @@ u16 get_unknown_box_id(void);
 bool8 InMultiBattleRoom(void);
 void sub_813BF10(void);
 void IncrementBirthIslandRockStepCount(void);
-bool8 sub_813B3B0(void);
+bool8 UnusualWeatherHasExpired(void);
 bool8 ShouldDoBrailleRegicePuzzle(void);
 bool32 is_tile_that_overrides_player_control(void);
 bool32 sub_8138120(void);
diff --git a/src/event_data.c b/src/event_data.c
index e75c37773..5ca288e7b 100644
--- a/src/event_data.c
+++ b/src/event_data.c
@@ -131,13 +131,13 @@ void sub_809D4D8(void)
 void sub_809D570(void)
 {
     VarSet(VAR_EVENT_PICHU_SLOT, 0);
-    VarSet(VAR_0x40DE, 0);
-    VarSet(VAR_0x40DF, 0);
-    VarSet(VAR_0x40E0, 0);
-    VarSet(VAR_0x40E1, 0);
-    VarSet(VAR_0x40E2, 0);
-    VarSet(VAR_0x40E3, 0);
-    VarSet(VAR_0x40E4, 0);
+    VarSet(VAR_NEVER_READ_0x40DE, 0);
+    VarSet(VAR_NEVER_READ_0x40DF, 0);
+    VarSet(VAR_NEVER_READ_0x40E0, 0);
+    VarSet(VAR_NEVER_READ_0x40E1, 0);
+    VarSet(VAR_NEVER_READ_0x40E2, 0);
+    VarSet(VAR_NEVER_READ_0x40E3, 0);
+    VarSet(VAR_NEVER_READ_0x40E4, 0);
 }
 
 void DisableResetRTC(void)
diff --git a/src/field_control_avatar.c b/src/field_control_avatar.c
index 90f7f4d5e..7bb2b257d 100644
--- a/src/field_control_avatar.c
+++ b/src/field_control_avatar.c
@@ -557,7 +557,7 @@ static bool8 TryStartStepCountScript(u16 metatileBehavior)
             ScriptContext1_SetupScript(EventScript_EggHatch);
             return TRUE;
         }
-        if (sub_813B3B0() == TRUE)
+        if (UnusualWeatherHasExpired() == TRUE)
         {
             ScriptContext1_SetupScript(UnusualWeather_EventScript_EndEventAndCleanup_1);
             return TRUE;
diff --git a/src/field_specials.c b/src/field_specials.c
index a5edb0122..7bfce8dd9 100644
--- a/src/field_specials.c
+++ b/src/field_specials.c
@@ -3424,7 +3424,7 @@ bool8 sub_813B260(void)
 void CreateUnusualWeatherEvent(void)
 {
     u16 randomValue = Random();
-    VarSet(VAR_0x4038, 0);
+    VarSet(VAR_UNUSUAL_WEATHER_STEP_COUNTER, 0);
 
     if (FlagGet(FLAG_DEFEATED_KYOGRE) == TRUE)
     {
@@ -3466,12 +3466,12 @@ bool32 GetUnusualWeatherMapNameAndType(void)
     }
 }
 
-bool8 sub_813B3B0(void)
+bool8 UnusualWeatherHasExpired(void)
 {
     // Duplicate array.
     static const u8 sUnusualWeatherMapNumbers_2[] = { 0x1d, 0x1d, 0x1e, 0x1e, 0x1f, 0x1f, 0x21, 0x21, 0x14, 0x14, 0x28, 0x28, 0x2a, 0x2a, 0x2c, 0x2c };
 
-    u16 var1 = VarGet(VAR_0x4038);
+    u16 steps = VarGet(VAR_UNUSUAL_WEATHER_STEP_COUNTER);
     u16 unusualWeather = VarGet(VAR_UNUSUAL_WEATHER_LOCATION);
 
     if (unusualWeather == UNUSUAL_WEATHER_NONE)
@@ -3479,9 +3479,9 @@ bool8 sub_813B3B0(void)
         return FALSE;
     }
 
-    if (++var1 > 999)
+    if (++steps > 999)
     {
-        VarSet(VAR_0x4038, 0);
+        VarSet(VAR_UNUSUAL_WEATHER_STEP_COUNTER, 0);
         if (gSaveBlock1Ptr->location.mapGroup == MAP_GROUP(UNDERWATER_MARINE_CAVE))
         {
             switch (gSaveBlock1Ptr->location.mapNum)
@@ -3491,7 +3491,7 @@ bool8 sub_813B3B0(void)
                 case MAP_NUM(MARINE_CAVE_END):
                 case MAP_NUM(TERRA_CAVE_ENTRANCE):
                 case MAP_NUM(TERRA_CAVE_END):
-                    VarSet(VAR_0x4039, 1);
+                    VarSet(VAR_SHOULD_END_UNUSUAL_WEATHER, 1);
                     return FALSE;
                 default:
                     break;
@@ -3506,7 +3506,7 @@ bool8 sub_813B3B0(void)
                 case MAP_NUM(UNDERWATER5):
                 case MAP_NUM(UNDERWATER6):
                 case MAP_NUM(UNDERWATER7):
-                    VarSet(VAR_0x4039, 1);
+                    VarSet(VAR_SHOULD_END_UNUSUAL_WEATHER, 1);
                     return FALSE;
                 default:
                     break;
@@ -3526,7 +3526,7 @@ bool8 sub_813B3B0(void)
     }
     else
     {
-        VarSet(VAR_0x4038, var1);
+        VarSet(VAR_UNUSUAL_WEATHER_STEP_COUNTER, steps);
         return FALSE;
     }
 }
diff --git a/src/overworld.c b/src/overworld.c
index edc4d402c..4206be448 100644
--- a/src/overworld.c
+++ b/src/overworld.c
@@ -408,9 +408,11 @@ static void Overworld_ResetStateAfterWhiteOut(void)
     FlagClear(FLAG_SYS_SAFARI_MODE);
     FlagClear(FLAG_SYS_USE_STRENGTH);
     FlagClear(FLAG_SYS_USE_FLASH);
-    if (VarGet(VAR_0x4039) == 1)
+    // If you were defeated by Kyogre/Groudon and the step counter has
+    // maxed out, end the unusual weather.
+    if (VarGet(VAR_SHOULD_END_UNUSUAL_WEATHER) == 1)
     {
-        VarSet(VAR_0x4039, 0);
+        VarSet(VAR_SHOULD_END_UNUSUAL_WEATHER, 0);
         VarSet(VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_NONE);
     }
 }