I'm working in a project currently that's being used in several countries with time-critical articles making up the meat of the web & mobile apps. We keep it simple and save all dates in UTC format in the database. It's then up to the client to take that date and display it in a local date + time. Because devices (browsers, smartphones) have their own date set (along with a timezone) it's very easy to localise the UTC dates/times for that device. For instance, in a web app a hugely popular date/time handling utility is Moment, which is flexible enough to accept a UTC time and return a time local to the device in whatever format is required, e.g. "Mon 18th Feb, 2017" It actually doesn't matter what timezone the dates are stored in the database as, so long as the client has the logic sufficent to be able to recognise the timezone the date was stored in and then be able to convert that time into one that is local to the client.