The timecyc.dat file contains the information for how to display the sky, weather effects and time of day. It is split into the many sections. There is one line of data per hour in the game, per weather type (except in San Andreas, where there are hours Midnight, 5AM, 6AM, 7AM, Midday, 7PM, 8PM, and 10PM. In the Vice City and San Andreas timecyc.dat, there is an extra section at the bottom of the file named "EXTRACOLOURS". These extra colours are used for building interiors, but should function the same.