Package timezone provides utility for timezone.
Package latlong maps from a latitude and longitude to a timezone. It uses the data from http://efele.net/maps/tz/world/ compressed down to an internal form optimized for low memory overhead and fast lookups at the expense of perfect accuracy when close to borders. The data files are compiled in to this package and do not require explicit loading.
Package tz contains time zone info so that you can predictably load Locations regardless of the locations available on the locally running operating system. The stdlib time.LoadLocation function loads timezone data from the operating system or from zoneinfo.zip in a local Go installation. Both of these are often missing from some operating systems, especially Windows. This package has the zoneinfo.zip from Go embedded into the package so that queries to load a location always return the same data regardless of operating system. This package exists because of https://github.com/golang/go/issues/21881.