diff --git a/src/overworld.c b/src/overworld.c
index 70b102fd2..3d46fc500 100644
--- a/src/overworld.c
+++ b/src/overworld.c
@@ -1260,23 +1260,34 @@ static void PlayAmbientCry(void)
     PlayCry_NormalNoDucking(sAmbientCrySpecies, pan, volume, CRY_PRIORITY_AMBIENT);
 }
 
+// States for UpdateAmbientCry
+enum {
+    AMB_CRY_INIT,
+    AMB_CRY_FIRST,
+    AMB_CRY_RESET,
+    AMB_CRY_WAIT,
+    AMB_CRY_IDLE,
+};
+
 void UpdateAmbientCry(s16 *state, u16 *delayCounter)
 {
     u8 i, monsCount, divBy;
 
     switch (*state)
     {
-    case 0:
+    case AMB_CRY_INIT:
+        // This state will be revisited whenever ResetFieldTasksArgs is called (which happens on map transition)
         if (sAmbientCrySpecies == SPECIES_NONE)
-            *state = 4;
+            *state = AMB_CRY_IDLE;
         else
-            *state = 1;
+            *state = AMB_CRY_FIRST;
         break;
-    case 1:
+    case AMB_CRY_FIRST:
+        // It takes between 1200-3599 frames (~20-60 seconds) to play the first ambient cry after entering a map
         *delayCounter = (Random() % 2400) + 1200;
-        *state = 3;
+        *state = AMB_CRY_WAIT;
         break;
-    case 2:
+    case AMB_CRY_RESET:
         divBy = 1;
         monsCount = CalculatePlayerPartyCount();
         for (i = 0; i < monsCount; i++)
@@ -1288,18 +1299,20 @@ void UpdateAmbientCry(s16 *state, u16 *delayCounter)
                 break;
             }
         }
+        // Ambient cries after the first one take between 1200-2399 frames (~20-40 seconds)
+        // If the player has a pokemon with the ability Swarm in their party, the time is halved to 600-1199 frames (~10-20 seconds)
         *delayCounter = ((Random() % 1200) + 1200) / divBy;
-        *state = 3;
+        *state = AMB_CRY_WAIT;
         break;
-    case 3:
-        (*delayCounter)--;
-        if (*delayCounter == 0)
+    case AMB_CRY_WAIT:
+        if (--(*delayCounter) == 0)
         {
             PlayAmbientCry();
-            *state = 2;
+            *state = AMB_CRY_RESET;
         }
         break;
-    case 4:
+    case AMB_CRY_IDLE:
+        // No land/water pokemon on this map
         break;
     }
 }