SharePoint is designed that people can use it from multiple time zones. For example, you might have offices in London, Paris and New York. 0700 hours in New York is not the same time as 0700 in Paris, as many transatlantic telephone calls will attest to. Further, many nations have a ‘summer’ and ‘winter’ time, which seems to have been introduced to annoy dairy farmers and computer programmers.
Thus, SharePoint needs a common way to store these times. It does this using UTC time (Coordinated Universal Time). This is, near enough, GMT, and it’s also called Zulu by pilots, the military, and pedants. 0700Z (the Z represents ‘Zulu’ as in ISO8601) is the same time whether you’re in London or Sydney – just in Sydney, 0700 Zulu is actually in the evening.
Now, you don’t need to worry about this, ‘cos SharePoint is smart enough to translate your local time to UTC when you set a date and time, and to translate it back again when displaying the date to you. Thus, 0700 in New York would be stored as 1100Z in the SharePoint database, and then when you looked at that document’s properties, it would be converted back to 0700. If you looked at the document in, say, London, it would convert 1100Z to 1200. (Well, all this is as happens today – summer/winter time makes things really hairy).
So where am I going with this? I have an application where you fill in a date and time, and submit it to SharePoint. When I get the dates back, though, the time is out by an hour. I’m in the UK and it’s summertime, so my timezone is actually UTC+1; therefore, time conversions seem likely to be the issue. Continue reading “SharePoint Web Services and UTC time fun and games”