Anybody that says it’s easy to deal with time zones has not programmed extensively with Time zones! This even extends to such common commands as Date.today, which can be yesterday or tomorrow given given the machine’s time zone.
References
This is a GREAT article: Working with time zones in Ruby on Rails.
Here’s a snippet from that article:
Do’s
2.hours.ago # => Thu, 27 Aug 2015 14:39:36 AFT +04:30
1.day.from_now # => Fri, 28 Aug 2015 16:39:36 AFT +04:30
Time.zone.parse("2015-08-27T12:09:36Z") # => Thu, 27 Aug 2015 16:39:36 AFT +04:30
Time.current # => Thu, 27 Aug 2015 16:39:36 AFT +04:30
Time.current.utc.iso8601 # When supliyng an API ("2015-08-27T12:09:36Z")
Time.strptime("2015-08-27T12:09:36Z", "%Y-%m-%dT%H:%M:%S%z").in_time_zone # If you can't use Time.zone.parse (Thu, 27 Aug 2015 16:39:36 AFT +04:30)
Date.current # If you really can't have a Time or DateTime for some reason (Thu, 27 Aug 2015)
Date.current.in_time_zone # If you have a date and want to make the best out of it (Thu, 27 Aug 2015 00:00:00 AFT +04:30)
D
Do nots
Time.now # Returns system time and ignores your configured time zone. (2015-08-27 14:09:36 +0200)
Time.parse("2015-08-27T12:09:36Z") # Will assume time string given is in the system's time zone. (2015-08-27 12:09:36 UTC)
Time.strptime("2015-08-27T12:09:36Z", "%Y-%m-%dT%H:%M:%S%z") # Same problem as with Time.parse. (2015-08-27 12:09:36 UTC)
Date.today # This could be yesterday or tomorrow depending on the machine's time zone, see https://github.com/ramhoj/time-zone-article/issues/1 for more info. (Thu, 27 Aug 2015)