This is surprisingly difficult task if you need it to work really globally and accurately. You need specific, detailed and uptodate map data for it, and timezones change somewhere in the world all the time. Especially daylight savigs. In 99% of cases you need to find some workaround or limit your task to specific regions, and get something to work in 95% cases

Ah, I haven’t seen a dataset I could use for that. Everything on the links I’m putting up is based on the country and state information.

I’ve seen timezone maps drawn, so this information does exist somewhere, but one would have to draw polygons for each timezone and do coverage checks, which seems complicated. The time zone lines zig and zag a lot.