How to reliably determine time zone for a user from the Twitter API?

Question

When getting information from Twitter\'s API for a user, they provide two fields related to the user\'s time zone:

utc_offset: -14400,
time_zone: \"Indiana (         


        

Answer 1

Twitter's front end uses Ruby on Rails. If you go to your own twitter account settings and look at the possible options for time zones (view source on the dropdown list), you will find that they match up with those provided by ActiveSupport::TimeZone, shown in this documentation. Although there appears to be some zones understood by Rails that Twitter has omitted, all of the Twitter zone key names are in that list.

I have asked Twitter to use standard time zone names in the future, in this developer request.

Why does Rails limit this list and use their own key values? Who knows. I have asked before, and gotten very little response. Read here.

But you can certainly use their mapping dictionary to turn the time_zone value into a standard IANA time zone identifier. For example:

• "Indiana (East)" => "America/Indiana/Indianapolis"
• "Central Time (US & Canada)" => "America/Chicago"

This can be found in the Rails documentation, and in the source code. (Scroll down to MAPPING.)

Then you can use any standard IANA/Olson/TZDB implementation you wish. They exist for just about every language and platform. For further details, see the timezone tag wiki. If you need help with a specific implementation, you'll need to expand your question to tell us what language you are using and what you have tried so far. (Or consider asking a new question about just that part of it.)

In regards to the utc_offset field, twitter does not make it clear what basis they use to calculate it. My guess is that it is the user's current offset, based on the time that you call the API.

Update 1

I have added support for converting Rails time zone names to both IANA and Windows standard time zone identifiers in my TimeZoneConverter library for .NET. If you are using .NET, you can use this library to simplify your conversions and stay on top of updates more easily.

Update 2

Twitter's API now returns the time zone in this format:

"time_zone": {
    "name": "Pacific Time (US & Canada)",
    "tzinfo_name": "America/Los_Angeles",
    "utc_offset": -28800
},

Use the tzinfo_name field. Done. :)