From Morrowind Modding Wiki
A function added by MGE XE.
XSetWeatherSky sets the sky color. You can also do it by editing morrowind.ini.
New values are not stored in savegames and will be lost when you exit the game. Setting weather data takes effect immediately.
XSetWeatherSky weatherID(float) time_enum(float) red(float) green(float) blue(float) weatherID -> weather type as used in ChangeWeather time_enum -> sunrise = 0, day = 1, sunset = 2, night = 3 rgb -> 0-255
short skycolor short rn short rn1 short rn2 short rn3 short rn4 short rn5 short rn6 short rn7 short rn8 short rn9 short rn10 short rn11 short weather short timeofday whilex ( skycolor ) set rn to random 255 ;random 256 crashes the game set rn1 to random 255 set rn2 to random 255 set rn3 to random 255 set rn4 to random 255 set rn5 to random 255 set rn6 to random 255 set rn7 to random 255 set rn8 to random 255 set rn9 to random 255 set rn10 to random 255 set rn11 to random 255 XSetWeatherSky weather timeofday rn rn1 rn2 XSetWeatherFog weather timeofday rn3 rn4 rn5 XSetWeatherAmbient weather timeofday rn6 rn7 rn8 XSetWeatherSun weather timeofday rn9 rn10 rn11 set timeofday to ( timeofday + 1 ) if ( timeofday == 4 ) set weather to ( weather + 1 ) set timeofday to 0 endif if ( weather == 10 ) set skycolor to 0 endif endwhile