> use that location to determine the correct timezone
Does this mean consult an "address to timezone lookup service?" Not sure if they exist, and I don't see another way without user specifying manually. Maybe a string match, but it could be wrong/unsure somewhat often.
> Then if Idaho decide to cancel daylight savings time you can update
Looking up events within a time interval is easy enough, those in city (timezone?) limits not so much. Consult a GIS system, search within polygons??? String match or every city in your database?
It's possible these days to run an entirely open source geocoding stack of your own. Here's one of the better options for that: https://github.com/osm-search/Nominatim
I wouldn't recommend it though: it needs a beefy machine and applying updates on an ongoing basis is fiddly. Better to use a commercial option and have that as an escape hatch.
> use that location to determine the correct timezone
Does this mean consult an "address to timezone lookup service?" Not sure if they exist, and I don't see another way without user specifying manually. Maybe a string match, but it could be wrong/unsure somewhat often.
> Then if Idaho decide to cancel daylight savings time you can update
Looking up events within a time interval is easy enough, those in city (timezone?) limits not so much. Consult a GIS system, search within polygons??? String match or every city in your database?