How do I know when it's daytime?
There are indicators on some maps
The time cycle does exist on all locations synchronally but on some maps it's barely to not visible at all.
For example, Concordia has an active day-to-night sky changing while Serenity's Waste has not, although they lay adjacent to each other. Maybe this is linked to Concordia being fully atmosphered and Serenity's Waste's environment is majorly vacuum. Sometimes day and night can only be separated by a slightly different lightning tone, where on nighttimes everything gets a blueish "hue" making everything look a bit colder. Often this effect gets nullified on maps with many fiery elements like Regolith Range. On inside-building maps, we can't tell at any chance if it's day or night.