diff --git a/include/d/d_kankyo.h b/include/d/d_kankyo.h
index 8ca2e2e59..51970bce9 100644
--- a/include/d/d_kankyo.h
+++ b/include/d/d_kankyo.h
@@ -383,6 +383,11 @@ enum dKy_dice_wether_state {
     /* 3 */ DICE_STATE_NEXT_e,
 };
 
+enum {
+    dKy_TIME_DAY_e = 0,
+    dKy_TIME_NIGHT_e = 1,
+};
+
 int dKy_getdaytime_hour();
 int dKy_getdaytime_minute();
 int dKy_get_dayofweek();
@@ -415,7 +420,7 @@ void dKy_plight_cut(LIGHT_INFLUENCE* param_0);
 cXyz dKy_plight_near_pos();
 void dKy_efplight_cut(LIGHT_INFLUENCE* param_0);
 void dKy_fog_startendz_set(f32, f32, f32);
-BOOL dKy_daynight_check();
+int dKy_daynight_check();
 void dKy_tevstr_init(dKy_tevstr_c*, s8, u8);
 void dKy_Sound_init();
 void dKy_change_colset(u8 param_0, u8 param_1, f32 param_2);
diff --git a/src/d/actor/d_a_npc_btsw2.cpp b/src/d/actor/d_a_npc_btsw2.cpp
index a214247d5..d10799216 100644
--- a/src/d/actor/d_a_npc_btsw2.cpp
+++ b/src/d/actor/d_a_npc_btsw2.cpp
@@ -283,7 +283,7 @@ u32 daNpc_Btsw2_c::getMsg() {
     if (!dComIfGs_isEventBit(0x3102)) {
         dComIfGs_onEventBit(0x3102);
         msgNo = 0x1AB0;
-    } else if (dKy_daynight_check()) {
+    } else if (dKy_daynight_check() != dKy_TIME_DAY_e) {
         msgNo = 0x1AB2;
     } else {
         msgNo = 0x1AB1;
diff --git a/src/d/actor/d_a_npc_people.cpp b/src/d/actor/d_a_npc_people.cpp
index b07a99f56..7d4995215 100644
--- a/src/d/actor/d_a_npc_people.cpp
+++ b/src/d/actor/d_a_npc_people.cpp
@@ -4197,7 +4197,7 @@ daNpcPeople_c::daNpcPeople_c() {
     m794 = 0;
     mEtcFlag = 0;
     m7A1 = 0;
-    mbIsNight = dKy_daynight_check() & 0x1; // this is weird but it generates the clrlwi
+    mbIsNight = dKy_daynight_check() & dKy_TIME_NIGHT_e; // this is weird but it generates the clrlwi
     mpNpcDat = l_npc_dat[mNpcType][mbIsNight];
     m730 = NULL;
 }
diff --git a/src/d/actor/d_a_obj_toripost.cpp b/src/d/actor/d_a_obj_toripost.cpp
index e9ae2b8df..227933633 100644
--- a/src/d/actor/d_a_obj_toripost.cpp
+++ b/src/d/actor/d_a_obj_toripost.cpp
@@ -368,7 +368,7 @@ int daObjTpost_c::getMsgNormal() {
         field_0x8EB = 0;
     }
     else {
-        if(dKy_daynight_check() == false) {
+        if(dKy_daynight_check() == dKy_TIME_DAY_e) {
             msgId = 0xCE5;
         }
         else {
diff --git a/src/d/d_com_static.cpp b/src/d/d_com_static.cpp
index 13da495c2..a3097339e 100644
--- a/src/d/d_com_static.cpp
+++ b/src/d/d_com_static.cpp
@@ -142,7 +142,7 @@ u8 daObjLight::Act_c::M_S_lod_access;
 /* 80056790-800567F8       .text renew_light_angle__Q210daObjLight5Act_cFv */
 bool daObjLight::Act_c::renew_light_angle() {
     M_S_lod_access = 1;
-    if (dKy_daynight_check() == 1) {
+    if (dKy_daynight_check() == dKy_TIME_NIGHT_e) {
         if (dComIfGs_isEventBit(0x1C02) == 1) {
             set_light_dif_angle_LOD(get_light_dif_angle() + 0x80);
             return true;
diff --git a/src/d/d_kankyo.cpp b/src/d/d_kankyo.cpp
index 48ba1a0f6..aaca7e9f0 100644
--- a/src/d/d_kankyo.cpp
+++ b/src/d/d_kankyo.cpp
@@ -533,7 +533,7 @@ void dScnKy_env_light_c::setDaytime() {
                 mDayOfWeek++;
                 dKankyo_DayProc();
             }
-        } else if (!dKy_daynight_check()) {
+        } else if (dKy_daynight_check() == dKy_TIME_DAY_e) {
             if (mCurTime < 165.0f) {
                 mCurTime += mTimeAdv;
             }
@@ -627,13 +627,13 @@ int dKy_getdaytime_minute() {
 }
 
 /* 80190CBC-80190CF8       .text dKy_daynight_check__Fv */
-BOOL dKy_daynight_check() {
+int dKy_daynight_check() {
     s32 hour = dKy_getdaytime_hour();
 
     if (hour >= 6 && hour < 18) {
-        return 0;  // day time
+        return dKy_TIME_DAY_e;
     } else {
-        return 1;  // night time
+        return dKy_TIME_NIGHT_e;
     }
 }
 
diff --git a/src/d/d_salvage.cpp b/src/d/d_salvage.cpp
index 140795f5b..3d54bf20c 100644
--- a/src/d/d_salvage.cpp
+++ b/src/d/d_salvage.cpp
@@ -102,7 +102,7 @@ void dSalvage_control_c::entry(fopAc_ac_c* pact, JPABaseEmitter* emtr) {
     case 4:
         if (saveNo != 31 && dComIfGs_isOceanSvBit(cmapNo, saveNo))
             return;
-        if (!dKy_daynight_check())
+        if (dKy_daynight_check() == dKy_TIME_DAY_e)
             mInfo[no].setFlag(1);
         break;
     case 6: