At 09:10 -0700 on 06/28/2014, Hardee, Chuck wrote about Re: Local
Time conversion to/from UTC Time:
I'm looking for information on how local time to UTC, and vice
versa, is affected by a locale's Daylight Savings Time state.
Converting UTC to Local time for historical data is no problem so
long as you know the DST switch dates for the locale. Switching from
local to UTC needs the same info but is harder for the FALL switch
date due to the repeat of the 1AM-1:59AM Hour since there are two of
them on switch date. If you have a series of time stamps (or no time
stamps for 1AM-1:59AM) then you just use a 1:xx time stamp occurring
after a much later 1:xx one to mark the switch from ST to DST. For
SPRING there will be no 2:xx so anything from 3AM on is ST.
