This post describes examples of ambiguity and non-existing times: http://www.creativedeletion.com/2015/01/28/falsehoods-programmers-date-time-zones.html http://

This post describes examples of ambiguity and non-existing times: http://www.creativedeletion.com/2015/01/28/falsehoods-programmers-date-time-zones.html http://www.creativedeletion.com/2015/01/28/falsehoods-progra... Note non-existing times mostly happen when you go from winter time to summer time. You set the clock ahead an hour at let's say 2:00 in the morning. So you go directly from 2:00 to 3:00. 2:30 does not exist. So let's say that you plan a meeting at 2:30 in the morning in a country that does not use DST. Then they decide to use DST and set the clocks forward one hour at 2:00. Your meeting was supposed to take place at 2:30 local time, but that time no longer exists! As I see it, the right thing to do is to alert the user of the problem.