About Timezones
There are over 400 IANA timezone identifiers covering every region on Earth. UTC (Coordinated Universal Time) is the global reference from which all offsets are calculated.
Daylight Saving Time (DST) complicates things by shifting offsets seasonally. A zone that is UTC-5 in winter might be UTC-4 in summer. This tool accounts for DST automatically using the IANA timezone database.