Time zone is a region in the galaxy, in a system or on a planet that has a uniform standard time for legal, commercial, and social purposes. Each race usually has one single official time zone while also having numerous different time zones for different systems and colonies. There is also one standard galactic time. Usually a specific location in the colony or system is the baseline for the time zone and rest of the time zones have various offsets based on this time zone. For example a time zone on some colony world might have time offset of +2 hours from the baseline zone.
Optional history here if it's deemed necessary.
All the major time zones are listed here. As there are numerous smaller time zones it would be near impossible to list them all and thus only selected ones are listed.
Galactic standard time
The galactic standard time is based on the rotation of the galaxy. However, as one galactic year is very long (approx. 225 million Earth years) it has been decided that one galactic standard year is 0.000001% of one galactic year (that is 2.25 Earth years). One galactic year is xxx days long and galactic day is xx hours.
Gigerdian standard time
The gigerdian standard time is based on the time zone used on Gigord, the Gigerdian capital. Gigord, however, is not the base time zone on Gigerdi Prime, but is rather offset by +6 hours from the base time zone. Gigerdian standard time has a day length of 27 hours and thus cannot really be compared with other time zones as both the clock hours and dates are different. A gigerdian year is 321 days long and 8667 standard hours long. This makes Gigerdian year approximately 0.9894 Earth years.
UCP standard time
UCP standard time is not based on any of the capital worlds, but rather is the weighted average of all the capital worlds. The weights have been selected so that there won't be huge differences between the time zones as some worlds have much longer days than others. Thus those with longer or shorter day lengths than most have smaller weights. Same goes with the year lengths. UCP standard day is 26 hours long and standard year is 370 days long.
HFed standard time
HFed Standard Time is the basic universal time specificiation used on all worlds of the Hemmoian Federation, based on the ancient system of Hemmoian chronology.
Folan standard time
Folan standard time is based on the time zone of Folan capital Verin which is also the base time zone on Folanus. Day length in Folan standard time is 23 hours and year length is 413 days.