The shift to DST is supposed to occur at 2:00am in the USA, regardless of your timezone, isn't it? Your job was scheduled to run at 1:00am. So if you're in the USA they shouldn't have bumped into each other, unless for some reason the switch occurred at the wrong time.

If you're in Europe, the switch occurrs at 1:00am Universal Time. So if you're in europe, it's possible that your cron job bumped into the DST switch.

The other thing to remember is that the clock doesn't actually change for DST. Your timezone changes. You go from, for example, Pacific Standard Time to Pacific Daylight Time. Unfortuantely, if I recall, cron isn't timezone aware, so there's a good chance that it does get confused when the computer's timezone changes and suddenly cron finds itself operating in an environment that thinks it's 3:00am local time versus 2:00am local time. In that case, jobs can get skipped, at least according to what bit of googling and reading I've done.