Note that the game changes between dawn, day, dusk and night only when you interact with traces or objects in the game. Feel free to let me know if you notice this calculator being more than 20-30 seconds off.
Most oddities appear only during certain times of day, only Centaurs can spawn at any time.
By combining your GPS coordinates with the date + timezone - this calculator will estimate the 4 phases in HPWU: dawn, day, dusk and night - and when each phase occurs. Feel free to let me know if you notice this calculator being more than 20-30 seconds incorrect.
That is understandable!