I'm working on an app that will be used by the public services (ambulance). Since those people work around the clock, they will realistically need to enter date/time values at ANY time of the day. Which also includes DST changeover times.
Now, when entering the time at the "short" day, things are easy. Simply any value between 3:00:00 and 3:59:59 is invalid. Problem is with the "long" day, where values in that same interval are ambiguous.
Is there any standard way/notation for entering time at that dreadful hour? Have you ever used any other workarounds, and which ones did your users find good?
Added: Also cloned on ux.stackexchange.