diff --git a/gamedata/scripts/lua_help_ex.script b/gamedata/scripts/lua_help_ex.script
index c4810e70e0..4a581727c4 100644
--- a/gamedata/scripts/lua_help_ex.script
+++ b/gamedata/scripts/lua_help_ex.script
@@ -583,6 +583,7 @@
         float get_weather_weight()
         void set_weather_weight(float)
         void set_weather_smooth(string)
+        void set_rain_wetness(float) // 0 to 1, read with level.rain_wetness()
 
         // Camera, position is x,y,z vector, direction is head,pitch,roll vector in RADIANS
         void set_cam_custom_position_direction(Fvector position, Fvector direction, int smoothing, bool hudDraw, bool hudAffect)
diff --git a/src/xrEngine/Environment_misc.cpp b/src/xrEngine/Environment_misc.cpp
index 5d5b47735b..40b1f33aa6 100644
--- a/src/xrEngine/Environment_misc.cpp
+++ b/src/xrEngine/Environment_misc.cpp
@@ -16,6 +16,9 @@ extern float ps_r2_sun_shafts_min;
 extern float ps_r2_sun_shafts_value;
 extern Fvector3 ssfx_wetness_multiplier;
 
+// seconds to fully wet or dry at multiplier 1
+static const float WETNESS_CHANGE_TIME = 166.f;
+
 void CEnvModifier::load(IReader* fs, u32 version)
 {
 	use_flags.one();
@@ -521,9 +524,9 @@ void CEnvDescriptorMixer::lerp(CEnvironment* env, CEnvDescriptor& A, CEnvDescrip
 	sun_color.lerp(A.sun_color, B.sun_color, f);
 
 	if (rain_density > 0.f)
-		env->wetness_factor += ( rain_density * ssfx_wetness_multiplier.x) / 10000.f;
+		env->wetness_factor += rain_density * ssfx_wetness_multiplier.x * Device.fTimeDelta / WETNESS_CHANGE_TIME;
 	else
-		env->wetness_factor -= 0.0001f * ssfx_wetness_multiplier.y;
+		env->wetness_factor -= ssfx_wetness_multiplier.y * Device.fTimeDelta / WETNESS_CHANGE_TIME;
 
 	clamp(env->wetness_factor, 0.f, 1.f);
 
diff --git a/src/xrGame/level_script.cpp b/src/xrGame/level_script.cpp
index 52aebcda7c..2643d4f41d 100644
--- a/src/xrGame/level_script.cpp
+++ b/src/xrGame/level_script.cpp
@@ -384,6 +384,12 @@ float rain_wetness()
 	return (g_pGamePersistent->Environment().wetness_factor);
 }
 
+void set_rain_wetness(float val)
+{
+	clamp(val, 0.f, 1.f);
+	g_pGamePersistent->Environment().wetness_factor = val;
+}
+
 float rain_hemi()
 {
 	CEffect_Rain* rain = g_pGamePersistent->pEnvironment->eff_Rain;
@@ -2728,6 +2734,7 @@ void CLevel::script_register(lua_State* L)
 			def("vertex_in_direction", vertex_in_direction),
 			def("rain_factor", rain_factor),
 			def("rain_wetness", rain_wetness),
+			def("set_rain_wetness", set_rain_wetness),
 			def("rain_hemi", rain_hemi),
 			def("patrol_path_exists", patrol_path_exists),
 			def("vertex_position", vertex_position),