This is a guide for editing timecycE.dat, timecycF.dat, timecycl.dat, timecycS.dat and timecycW.dat.
Amb_Props - ambient lights for animated props
Amb_World - ambient light for the world
Amb_Peds - ambient light for cars, peds and dynamic objects
Sun RGB - Sun RGBectional light used for cars and peds (RGB)
Back - Back lighting opposite to Sun RGB light and also used for cars and peds (RGB)
BackInt - Back lighting intensity modifier
SKYTOP - colour of the sky gradient at top (RGB)
Sky bot - colour of the sky gradient at bottom (RGB)
Sun RGBcore - colour of the centre of the Sun RGB (RGB)
Sun RGBcorona - colour of the glow around the Sun RGB (RGB)
Sun RGBsz - size of the Sun RGB
Sprsz - multiplier for the size of sprites
Sprbrght - brightness of sprites
Shdw - alpha of cast shadows (don’t think its used anymore)
Lightshd - alpha for cast light (traffic lights or lampposts)
Poleshd - alpha for the shadow of poles (lampposts)
Farclip - fairly obvious sets far clip plane for the game
Fogst - distance the fog starts from the camera (can be negative)
Lightonground - unknown
lowcloudsRGB - colour of the long thin clouds (RGB)
TopCloudRGB - colour of the top of the big clouds (RGB)
BottomCloudRGB - colour of the bottom of the big clouds (RGB)
BLURRGB - the colour of the overlay used when the game has motion blur on RGBA but in vc the drawmode for the overlay was additive and the alpha has no effect. High nubers mean very very blurry
waterRGBA - used to colour dynamic water and set transparency.
GlowThresh - Threshold for the Glow effect
GlowStrength - The strength of glow
CloudSpeed - how fast the sky dome rotates
CloudTopRGB- cpv for the sky dome top layer
CloudBotRGB- cpv for the sky dome bottom layer
ColFilterMode - full-screen color filter mode: 0-disable, 1-modulate, 2-add
BackHRange - color to use
AmbLRange - Ambient value lower range
AmbHRange - Ambient value higher range
SunLRange - Sun light lower range
SunHRange - Sun light higher range
BackLRange - Back light lower range
BackHRange - Back light higher range
NearFarRatio - Maximum ratio between near and far clip plane
*thanks to Rockstar Games