Reverse engineer unusual weather events

18 files changed, 115 insertions, 87 deletions

diff --git a/data/event_scripts.s b/data/event_scripts.s
index 55bbb7618..adecc3fcf 100644
--- a/data/event_scripts.s
+++ b/data/event_scripts.s
@@ -3188,7 +3188,7 @@ gUnknown_08273D1F:: @ 8273D1F
 
 gUnknown_08273D1F:: @ 8273D1F
 	lockall
-	compare VAR_0x4037, 9
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_KYOGRE_LOCATIONS_START
 	goto_if_ge Route105_EventScript_273D51
 	goto Route105_EventScript_273D5F
 	end
@@ -3200,7 +3200,7 @@ Route105_EventScript_273D31:: @ 8273D31
 	doweather
 	call Route105_EventScript_273D6D
 	special DrawWholeMapView
-	setvar VAR_0x4037, 0
+	setvar VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_NONE
 	setvar VAR_0x4039, 0
 	clearflag FLAG_SPECIAL_FLAG_0x4000
 	fadescreenswapbuffers 0
@@ -3218,23 +3218,23 @@ Route105_EventScript_273D5F:: @ 8273D5F
 	end
 
 Route105_EventScript_273D6D:: @ 8273D6D
-	switch VAR_0x4037
-	case 1, Route105_EventScript_273E23
-	case 2, Route105_EventScript_273E36
-	case 3, Route105_EventScript_273E49
-	case 4, Route105_EventScript_273E5C
-	case 5, Route105_EventScript_273E6F
-	case 6, Route105_EventScript_273E82
-	case 7, Route105_EventScript_273E95
-	case 8, Route105_EventScript_273EA8
-	case 9, Route105_EventScript_273EBB
-	case 10, Route105_EventScript_273F28
-	case 11, Route105_EventScript_273F95
-	case 12, Route105_EventScript_274002
-	case 13, Route105_EventScript_27406F
-	case 14, Route105_EventScript_2740DC
-	case 15, Route105_EventScript_274149
-	case 16, Route105_EventScript_2741B6
+	switch VAR_UNUSUAL_WEATHER_LOCATION
+	case UNUSUAL_WEATHER_ROUTE_114_NORTH, Route105_EventScript_273E23
+	case UNUSUAL_WEATHER_ROUTE_114_SOUTH, Route105_EventScript_273E36
+	case UNUSUAL_WEATHER_ROUTE_115_WEST, Route105_EventScript_273E49
+	case UNUSUAL_WEATHER_ROUTE_115_EAST, Route105_EventScript_273E5C
+	case UNUSUAL_WEATHER_ROUTE_116_NORTH, Route105_EventScript_273E6F
+	case UNUSUAL_WEATHER_ROUTE_116_SOUTH, Route105_EventScript_273E82
+	case UNUSUAL_WEATHER_ROUTE_118_EAST, Route105_EventScript_273E95
+	case UNUSUAL_WEATHER_ROUTE_118_WEST, Route105_EventScript_273EA8
+	case UNUSUAL_WEATHER_ROUTE_105_NORTH, Route105_EventScript_273EBB
+	case UNUSUAL_WEATHER_ROUTE_105_SOUTH, Route105_EventScript_273F28
+	case UNUSUAL_WEATHER_ROUTE_125_WEST, Route105_EventScript_273F95
+	case UNUSUAL_WEATHER_ROUTE_125_EAST, Route105_EventScript_274002
+	case UNUSUAL_WEATHER_ROUTE_127_NORTH, Route105_EventScript_27406F
+	case UNUSUAL_WEATHER_ROUTE_127_SOUTH, Route105_EventScript_2740DC
+	case UNUSUAL_WEATHER_ROUTE_129_WEST, Route105_EventScript_274149
+	case UNUSUAL_WEATHER_ROUTE_129_EAST, Route105_EventScript_2741B6
 	return
 
 Route105_EventScript_273E23:: @ 8273E23
@@ -3401,15 +3401,15 @@ Underwater3_EventScript_274223:: @ 8274223
 Underwater5_EventScript_274223:: @ 8274223
 Underwater6_EventScript_274223:: @ 8274223
 Underwater7_EventScript_274223:: @ 8274223
-	switch VAR_0x4037
-	case 9, Underwater3_EventScript_274281
-	case 10, Underwater3_EventScript_27428A
-	case 11, Underwater3_EventScript_274293
-	case 12, Underwater3_EventScript_27429C
-	case 13, Underwater3_EventScript_2742A5
-	case 14, Underwater3_EventScript_2742AE
-	case 15, Underwater3_EventScript_2742B7
-	case 16, Underwater3_EventScript_2742C0
+	switch VAR_UNUSUAL_WEATHER_LOCATION
+	case UNUSUAL_WEATHER_ROUTE_105_NORTH, Underwater3_EventScript_274281
+	case UNUSUAL_WEATHER_ROUTE_105_SOUTH, Underwater3_EventScript_27428A
+	case UNUSUAL_WEATHER_ROUTE_125_WEST, Underwater3_EventScript_274293
+	case UNUSUAL_WEATHER_ROUTE_125_EAST, Underwater3_EventScript_27429C
+	case UNUSUAL_WEATHER_ROUTE_127_NORTH, Underwater3_EventScript_2742A5
+	case UNUSUAL_WEATHER_ROUTE_127_SOUTH, Underwater3_EventScript_2742AE
+	case UNUSUAL_WEATHER_ROUTE_129_WEST, Underwater3_EventScript_2742B7
+	case UNUSUAL_WEATHER_ROUTE_129_EAST, Underwater3_EventScript_2742C0
 	return
 
 Underwater3_EventScript_274281:: @ 8274281
diff --git a/data/maps/Route105/scripts.inc b/data/maps/Route105/scripts.inc
index 6ad11bc52..74416f153 100644
--- a/data/maps/Route105/scripts.inc
+++ b/data/maps/Route105/scripts.inc
@@ -6,9 +6,9 @@ Route105_MapScripts:: @ 81EE1DB
 
 Route105_MapScript1_1EE1EB: @ 81EE1EB
 	call_if_unset FLAG_REGI_DOORS_OPENED, Route105_EventScript_1EE20B
-	compare VAR_0x4037, 9
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_105_NORTH
 	call_if_eq Route105_EventScript_2739AB
-	compare VAR_0x4037, 10
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_105_SOUTH
 	call_if_eq Route105_EventScript_273A18
 	end
 
@@ -20,9 +20,9 @@ Route105_EventScript_1EE20B:: @ 81EE20B
 Route105_MapScript1_1EE21E: @ 81EE21E
 	compare VAR_0x4039, 1
 	call_if_eq Route105_EventScript_273D13
-	compare VAR_0x4037, 9
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_105_NORTH
 	call_if_eq Route105_EventScript_273D17
-	compare VAR_0x4037, 10
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_105_SOUTH
 	call_if_eq Route105_EventScript_273D17
 	end
 
diff --git a/data/maps/Route114/scripts.inc b/data/maps/Route114/scripts.inc
index d4327a2f4..856a0f1e4 100644
--- a/data/maps/Route114/scripts.inc
+++ b/data/maps/Route114/scripts.inc
@@ -7,16 +7,16 @@ Route114_MapScripts:: @ 81F252F
 Route114_MapScript1_1F253F: @ 81F253F
 	compare VAR_0x4039, 1
 	call_if_eq Route114_EventScript_273D13
-	compare VAR_0x4037, 1
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_114_NORTH
 	call_if_eq Route114_EventScript_273D1B
-	compare VAR_0x4037, 2
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_114_SOUTH
 	call_if_eq Route114_EventScript_273D1B
 	end
 
 Route114_MapScript1_1F2561: @ 81F2561
-	compare VAR_0x4037, 1
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_114_NORTH
 	call_if_eq Route114_EventScript_273913
-	compare VAR_0x4037, 2
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_114_SOUTH
 	call_if_eq Route114_EventScript_273926
 	end
 
diff --git a/data/maps/Route115/scripts.inc b/data/maps/Route115/scripts.inc
index 9cb3ea2e0..42cf643af 100644
--- a/data/maps/Route115/scripts.inc
+++ b/data/maps/Route115/scripts.inc
@@ -5,18 +5,18 @@ Route115_MapScripts:: @ 81F2920
 	.byte 0
 
 Route115_MapScript1_1F2930: @ 81F2930
-	compare VAR_0x4037, 3
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_115_WEST
 	call_if_eq Route115_EventScript_273939
-	compare VAR_0x4037, 4
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_115_EAST
 	call_if_eq Route115_EventScript_27394C
 	end
 
 Route115_MapScript1_1F2947: @ 81F2947
 	compare VAR_0x4039, 1
 	call_if_eq Route115_EventScript_273D13
-	compare VAR_0x4037, 3
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_115_WEST
 	call_if_eq Route115_EventScript_273D1B
-	compare VAR_0x4037, 4
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_115_EAST
 	call_if_eq Route115_EventScript_273D1B
 	end
 
diff --git a/data/maps/Route116/scripts.inc b/data/maps/Route116/scripts.inc
index 90ae29f5b..afb0505c8 100644
--- a/data/maps/Route116/scripts.inc
+++ b/data/maps/Route116/scripts.inc
@@ -8,9 +8,9 @@ Route116_MapScript1_1F2C1C: @ 81F2C1C
 	call_if_set FLAG_RECOVERED_DEVON_GOODS, Route116_EventScript_1F2C47
 	compare VAR_0x4039, 1
 	call_if_eq Route116_EventScript_273D13
-	compare VAR_0x4037, 5
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_116_NORTH
 	call_if_eq Route116_EventScript_273D1B
-	compare VAR_0x4037, 6
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_116_SOUTH
 	call_if_eq Route116_EventScript_273D1B
 	end
 
@@ -19,9 +19,9 @@ Route116_EventScript_1F2C47:: @ 81F2C47
 	return
 
 Route116_MapScript1_1F2C4F: @ 81F2C4F
-	compare VAR_0x4037, 5
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_116_NORTH
 	call_if_eq Route116_EventScript_27395F
-	compare VAR_0x4037, 6
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_116_SOUTH
 	call_if_eq Route116_EventScript_273972
 	end
 
diff --git a/data/maps/Route118/scripts.inc b/data/maps/Route118/scripts.inc
index 758804137..88c4e1275 100644
--- a/data/maps/Route118/scripts.inc
+++ b/data/maps/Route118/scripts.inc
@@ -8,16 +8,16 @@ Route118_MapScript1_1F3DCC: @ 81F3DCC
 	call Route118_EventScript_28CCC7
 	compare VAR_0x4039, 1
 	call_if_eq Route118_EventScript_273D13
-	compare VAR_0x4037, 7
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_118_EAST
 	call_if_eq Route118_EventScript_273D1B
-	compare VAR_0x4037, 8
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_118_WEST
 	call_if_eq Route118_EventScript_273D1B
 	end
 
 Route118_MapScript1_1F3DF3: @ 81F3DF3
-	compare VAR_0x4037, 7
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_118_EAST
 	call_if_eq Route118_EventScript_273985
-	compare VAR_0x4037, 8
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_118_WEST
 	call_if_eq Route118_EventScript_273998
 	end
 
diff --git a/data/maps/Route119_WeatherInstitute_2F/scripts.inc b/data/maps/Route119_WeatherInstitute_2F/scripts.inc
index 7d557fdef..2eaeceb2f 100644
--- a/data/maps/Route119_WeatherInstitute_2F/scripts.inc
+++ b/data/maps/Route119_WeatherInstitute_2F/scripts.inc
@@ -137,11 +137,13 @@ Route119_WeatherInstitute_2F_EventScript_2700F7:: @ 82700F7
 	end
 
 Route119_WeatherInstitute_2F_EventScript_27010A:: @ 827010A
+    @ This code uses VAR_0x8004 to count the number of legendaries the player has defeated
+    @ already.
 	setvar VAR_0x8004, 0
-	call_if_set FLAG_DEFEATED_KYOGRE, Route119_WeatherInstitute_2F_EventScript_270160
-	call_if_set FLAG_DEFEATED_GROUDON, Route119_WeatherInstitute_2F_EventScript_270160
+	call_if_set FLAG_DEFEATED_KYOGRE, WeatherInstitute_UnusualWeather_IncrementLegendCount
+	call_if_set FLAG_DEFEATED_GROUDON, WeatherInstitute_UnusualWeather_IncrementLegendCount
 	compare VAR_0x8004, 2
-	goto_if_eq Route119_WeatherInstitute_2F_EventScript_270166
+	goto_if_eq WeatherInstitute_UnusualWeather_LegendariesAlreadyDefeated
 	call_if_unset FLAG_TEMP_2, Route119_WeatherInstitute_2F_EventScript_270159
 	specialvar VAR_RESULT, sub_813B374
 	compare VAR_RESULT, 1
@@ -156,16 +158,16 @@ Route119_WeatherInstitute_2F_EventScript_27014F:: @ 827014F
 	end
 
 Route119_WeatherInstitute_2F_EventScript_270159:: @ 8270159
-	special sub_813B2E4
+	special CreateUnusualWeatherEvent
 	setflag FLAG_TEMP_2
 	return
 
-Route119_WeatherInstitute_2F_EventScript_270160:: @ 8270160
+WeatherInstitute_UnusualWeather_IncrementLegendCount:: @ 8270160
 	addvar VAR_0x8004, 1
 	return
 
-Route119_WeatherInstitute_2F_EventScript_270166:: @ 8270166
-	msgbox Route119_WeatherInstitute_2F_Text_2708FC, MSGBOX_DEFAULT
+WeatherInstitute_UnusualWeather_LegendariesAlreadyDefeated:: @ 8270166
+	msgbox WeatherInstitute_UnusualWeather_LegendariesAlreadyDefeatedText, MSGBOX_DEFAULT
 	release
 	end
 
@@ -325,7 +327,7 @@ Route119_WeatherInstitute_2F_Text_270873: @ 8270873
 	.string "Could that mean, somewhere near\n"
 	.string "{STR_VAR_1}…$"
 
-Route119_WeatherInstitute_2F_Text_2708FC: @ 82708FC
+WeatherInstitute_UnusualWeather_LegendariesAlreadyDefeatedText: @ 82708FC
 	.string "Abnormal weather conditions are\n"
 	.string "no longer being reported.\p"
 	.string "The occasional rainfall is a blessing,\n"
diff --git a/data/maps/Route125/scripts.inc b/data/maps/Route125/scripts.inc
index 4812b9691..d1046e6a4 100644
--- a/data/maps/Route125/scripts.inc
+++ b/data/maps/Route125/scripts.inc
@@ -8,16 +8,16 @@ Route125_MapScript1_1F6758: @ 81F6758
 	call_if_set FLAG_SYS_WEATHER_CTRL, Common_EventScript_SetWeather15
 	compare VAR_0x4039, 1
 	call_if_eq Route125_EventScript_273D13
-	compare VAR_0x4037, 11
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_125_WEST
 	call_if_eq Route125_EventScript_273D17
-	compare VAR_0x4037, 12
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_125_EAST
 	call_if_eq Route125_EventScript_273D17
 	end
 
 Route125_MapScript1_1F6783: @ 81F6783
-	compare VAR_0x4037, 11
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_125_WEST
 	call_if_eq Route125_EventScript_273A85
-	compare VAR_0x4037, 12
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_125_EAST
 	call_if_eq Route125_EventScript_273AF2
 	end
 
diff --git a/data/maps/Route127/scripts.inc b/data/maps/Route127/scripts.inc
index 7d5eee844..9f2018e8f 100644
--- a/data/maps/Route127/scripts.inc
+++ b/data/maps/Route127/scripts.inc
@@ -8,16 +8,16 @@ Route127_MapScript1_1F69E9: @ 81F69E9
 	call_if_set FLAG_SYS_WEATHER_CTRL, Common_EventScript_SetWeather15
 	compare VAR_0x4039, 1
 	call_if_eq Route127_EventScript_273D13
-	compare VAR_0x4037, 13
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_127_NORTH
 	call_if_eq Route127_EventScript_273D17
-	compare VAR_0x4037, 14
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_127_SOUTH
 	call_if_eq Route127_EventScript_273D17
 	end
 
 Route127_MapScript1_1F6A14: @ 81F6A14
-	compare VAR_0x4037, 13
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_127_NORTH
 	call_if_eq Route127_EventScript_273B5F
-	compare VAR_0x4037, 14
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_127_SOUTH
 	call_if_eq Route127_EventScript_273BCC
 	end
 
diff --git a/data/maps/Route129/scripts.inc b/data/maps/Route129/scripts.inc
index 8aec4bc28..5f65712d7 100644
--- a/data/maps/Route129/scripts.inc
+++ b/data/maps/Route129/scripts.inc
@@ -5,9 +5,9 @@ Route129_MapScripts:: @ 81F7284
 	.byte 0
 
 Route129_MapScript1_1F7294: @ 81F7294
-	compare VAR_0x4037, 15
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_129_WEST
 	call_if_eq Route129_EventScript_273C39
-	compare VAR_0x4037, 16
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_129_EAST
 	call_if_eq Route129_EventScript_273CA6
 	end
 
@@ -16,9 +16,9 @@ Route129_MapScript1_1F72AB: @ 81F72AB
 	call_if_eq Route129_EventScript_273D13
 	compare VAR_0x405E, 4
 	call_if_ge Route129_EventScript_1F72D8
-	compare VAR_0x4037, 15
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_129_WEST
 	call_if_eq Route129_EventScript_273D17
-	compare VAR_0x4037, 16
+	compare VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_ROUTE_129_EAST
 	call_if_eq Route129_EventScript_273D17
 	end
 
diff --git a/data/specials.inc b/data/specials.inc
index 965bef117..193af9e86 100644
--- a/data/specials.inc
+++ b/data/specials.inc
@@ -499,7 +499,7 @@ gSpecials:: @ 81DBA64
 	def_special sub_813B21C
 	def_special SetMatchCallRegisteredFlag
 	def_special sub_8175280
-	def_special sub_813B2E4
+	def_special CreateUnusualWeatherEvent
 	def_special sub_813B374
 	def_special sub_813B490
 	def_special sub_80A08CC
diff --git a/include/constants/flags.h b/include/constants/flags.h
index b440ba78b..f0759389f 100644
--- a/include/constants/flags.h
+++ b/include/constants/flags.h
@@ -236,7 +236,7 @@
 #define FLAG_MET_WAILMER_TRAINER             0xDA
 #define FLAG_EVIL_LEADER_PLEASE_STOP         0xDB
 
-#define FLAG_UNUSED_0x0DC                    0xDC // Unused Flag
+#define FLAG_NEVER_SET_0x0DC                 0xDC // This flag is read, but never written to
 
 #define FLAG_RECEIVED_GO_GOGGLES             0xDD
 #define FLAG_WINGULL_SENT_ON_ERRAND          0xDE
diff --git a/include/constants/vars.h b/include/constants/vars.h
index fc3b3263d..9f364416c 100644
--- a/include/constants/vars.h
+++ b/include/constants/vars.h
@@ -60,7 +60,7 @@
 #define VAR_POISON_STEP_COUNTER              0x402B
 #define VAR_RESET_RTC_ENABLE                 0x402C
 #define VAR_ENIGMA_BERRY_AVAILABLE           0x402D
-#define VAR_0x402E                           0x402E   // Seems to be unused.
+#define VAR_UNUSED_0x402E                    0x402E // Unused Var
 
 #define VAR_FRONTIER_MANIAC_FACILITY         0x402F
 #define VAR_FRONTIER_GAMBLER_FACILITY        0x4030
@@ -71,7 +71,7 @@
 #define VAR_DEOXYS_ROCK_STEP_COUNT           0x4034
 #define VAR_DEOXYS_ROCK_LEVEL                0x4035
 #define VAR_STORAGE_UNKNOWN                  0x4036
-#define VAR_0x4037                           0x4037
+#define VAR_UNUSUAL_WEATHER_LOCATION                           0x4037
 #define VAR_0x4038                           0x4038
 #define VAR_0x4039                           0x4039
 #define VAR_0x403A                           0x403A
diff --git a/include/constants/weather.h b/include/constants/weather.h
index d62e07474..b01cfb390 100644
--- a/include/constants/weather.h
+++ b/include/constants/weather.h
@@ -37,4 +37,30 @@
 #define COORD_EVENT_WEATHER_ROUTE119_CYCLE 20
 #define COORD_EVENT_WEATHER_ROUTE123_CYCLE 21
 
+// These are the "unusual weather events" that are used
+// to find Kyogre and Groudon.
+#define UNUSUAL_WEATHER_COUNT_PER_LEGENDARY 8
+#define UNUSUAL_WEATHER_GROUDON_LOCATIONS_START 1
+#define UNUSUAL_WEATHER_KYOGRE_LOCATIONS_START 1 + UNUSUAL_WEATHER_COUNT_PER_LEGENDARY
+
+#define UNUSUAL_WEATHER_NONE 0
+// Groudon locations
+#define UNUSUAL_WEATHER_ROUTE_114_NORTH 1
+#define UNUSUAL_WEATHER_ROUTE_114_SOUTH 2
+#define UNUSUAL_WEATHER_ROUTE_115_WEST 3
+#define UNUSUAL_WEATHER_ROUTE_115_EAST 4
+#define UNUSUAL_WEATHER_ROUTE_116_NORTH 5
+#define UNUSUAL_WEATHER_ROUTE_116_SOUTH 6
+#define UNUSUAL_WEATHER_ROUTE_118_EAST 7
+#define UNUSUAL_WEATHER_ROUTE_118_WEST 8
+// Kyogre locations
+#define UNUSUAL_WEATHER_ROUTE_105_NORTH 9
+#define UNUSUAL_WEATHER_ROUTE_105_SOUTH 10
+#define UNUSUAL_WEATHER_ROUTE_125_WEST 11
+#define UNUSUAL_WEATHER_ROUTE_125_EAST 12
+#define UNUSUAL_WEATHER_ROUTE_127_NORTH 13
+#define UNUSUAL_WEATHER_ROUTE_127_SOUTH 14
+#define UNUSUAL_WEATHER_ROUTE_129_WEST 15
+#define UNUSUAL_WEATHER_ROUTE_129_EAST 16
+
 #endif // GUARD_CONSTANTS_WEATHER_H
diff --git a/src/field_specials.c b/src/field_specials.c
index 307f81399..1accaa5e5 100644
--- a/src/field_specials.c
+++ b/src/field_specials.c
@@ -3421,28 +3421,28 @@ bool8 sub_813B260(void)
     return FALSE;
 }
 
-void sub_813B2E4(void)
+void CreateUnusualWeatherEvent(void)
 {
     u16 randomValue = Random();
     VarSet(VAR_0x4038, 0);
 
     if (FlagGet(FLAG_DEFEATED_KYOGRE) == TRUE)
     {
-        VarSet(VAR_0x4037, (randomValue & 7) + 1);
+        VarSet(VAR_UNUSUAL_WEATHER_LOCATION, (randomValue & (UNUSUAL_WEATHER_COUNT_PER_LEGENDARY - 1)) + UNUSUAL_WEATHER_GROUDON_LOCATIONS_START);
     }
     else if (FlagGet(FLAG_DEFEATED_GROUDON) == TRUE)
     {
-        VarSet(VAR_0x4037, (randomValue & 7) + 9);
+        VarSet(VAR_UNUSUAL_WEATHER_LOCATION, (randomValue & (UNUSUAL_WEATHER_COUNT_PER_LEGENDARY - 1)) + UNUSUAL_WEATHER_KYOGRE_LOCATIONS_START);
     }
     else if ((randomValue & 1) == 0)
     {
         randomValue = Random();
-        VarSet(VAR_0x4037, (randomValue & 7) + 1);
+        VarSet(VAR_UNUSUAL_WEATHER_LOCATION, (randomValue & (UNUSUAL_WEATHER_COUNT_PER_LEGENDARY - 1)) + UNUSUAL_WEATHER_GROUDON_LOCATIONS_START);
     }
     else
     {
         randomValue = Random();
-        VarSet(VAR_0x4037, (randomValue & 7) + 9);
+        VarSet(VAR_UNUSUAL_WEATHER_LOCATION, (randomValue & (UNUSUAL_WEATHER_COUNT_PER_LEGENDARY - 1)) + UNUSUAL_WEATHER_KYOGRE_LOCATIONS_START);
     }
 }
 
@@ -3450,7 +3450,7 @@ bool32 sub_813B374(void)
 {
     static const u8 gUnknown_085B3400[] = { 0x1d, 0x1d, 0x1e, 0x1e, 0x1f, 0x1f, 0x21, 0x21, 0x14, 0x14, 0x28, 0x28, 0x2a, 0x2a, 0x2c, 0x2c };
 
-    u16 var = VarGet(VAR_0x4037);
+    u16 var = VarGet(VAR_UNUSUAL_WEATHER_LOCATION);
 
     GetMapName(gStringVar1, gUnknown_085B3400[var - 1], 0);
 
@@ -3466,12 +3466,12 @@ bool32 sub_813B374(void)
 
 bool8 sub_813B3B0(void)
 {
-    static const u8 gUnknown_085B3410[] = { 0x1d, 0x1d, 0x1e, 0x1e, 0x1f, 0x1f, 0x21, 0x21, 0x14, 0x14, 0x28, 0x28, 0x2a, 0x2a, 0x2c, 0x2c };
+    static const u8 sUnusualWeatherMapNumbers[] = { 0x1d, 0x1d, 0x1e, 0x1e, 0x1f, 0x1f, 0x21, 0x21, 0x14, 0x14, 0x28, 0x28, 0x2a, 0x2a, 0x2c, 0x2c };
 
     u16 var1 = VarGet(VAR_0x4038);
-    u16 var2 = VarGet(VAR_0x4037);
+    u16 unusualWeather = VarGet(VAR_UNUSUAL_WEATHER_LOCATION);
 
-    if (!var2)
+    if (unusualWeather == UNUSUAL_WEATHER_NONE)
     {
         return FALSE;
     }
@@ -3510,14 +3510,14 @@ bool8 sub_813B3B0(void)
             }
         }
 
-        if (gSaveBlock1Ptr->location.mapNum == gUnknown_085B3410[var2 - 1] &&
+        if (gSaveBlock1Ptr->location.mapNum == sUnusualWeatherMapNumbers[unusualWeather - 1] &&
             gSaveBlock1Ptr->location.mapGroup == 0)
         {
             return TRUE;
         }
         else
         {
-            VarSet(VAR_0x4037, 0);
+            VarSet(VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_NONE);
             return FALSE;
         }
     }
diff --git a/src/match_call.c b/src/match_call.c
index e7e91969f..de1181e8b 100644
--- a/src/match_call.c
+++ b/src/match_call.c
@@ -1016,7 +1016,7 @@ static bool32 MapAllowsMatchCall(void)
     
     if (gMapHeader.regionMapSectionId == MAPSEC_SOOTOPOLIS_CITY
      && FlagGet(FLAG_HIDE_SOOTOPOLIS_CITY_RAYQUAZA) == TRUE
-     && FlagGet(FLAG_UNUSED_0x0DC) == FALSE)
+     && FlagGet(FLAG_NEVER_SET_0x0DC) == FALSE)
         return FALSE;
 
     if (gMapHeader.regionMapSectionId == MAPSEC_MT_CHIMNEY
diff --git a/src/overworld.c b/src/overworld.c
index a10d1e17a..edc4d402c 100644
--- a/src/overworld.c
+++ b/src/overworld.c
@@ -411,7 +411,7 @@ static void Overworld_ResetStateAfterWhiteOut(void)
     if (VarGet(VAR_0x4039) == 1)
     {
         VarSet(VAR_0x4039, 0);
-        VarSet(VAR_0x4037, 0);
+        VarSet(VAR_UNUSUAL_WEATHER_LOCATION, UNUSUAL_WEATHER_NONE);
     }
 }
 
diff --git a/src/region_map.c b/src/region_map.c
index ff0c19167..5c85606a8 100644
--- a/src/region_map.c
+++ b/src/region_map.c
@@ -1159,7 +1159,7 @@ static u16 RegionMap_GetTerraCaveMapSecId(void)
 {
     s16 idx;
 
-    idx = VarGet(VAR_0x4037) - 1;
+    idx = VarGet(VAR_UNUSUAL_WEATHER_LOCATION) - 1;
     if (idx < 0 || idx > 15)
     {
         idx = 0;
@@ -1171,7 +1171,7 @@ static void RegionMap_GetMarineCaveCoords(u16 *x, u16 *y)
 {
     u16 idx;
 
-    idx = VarGet(VAR_0x4037);
+    idx = VarGet(VAR_UNUSUAL_WEATHER_LOCATION);
     if (idx < 9 || idx > 16)
     {
         idx = 9;