Our company runs a SaaS application where users log in from across the world (although mostly in the US). We store all our time relevant information as UTC, but we need to display times using local time. The application is web based, and we would like to “auto-detect” the user’s Time Zone by using javascript to determine their UTC offsets during various times of the year. The user’s offset info would be passed to our server in their first request and the server will look up all the Time Zones that it knows about and see which valid time zones match.