Why 1:30 AM Happens Twice When DST Ends
The fall-back transition creates an ambiguous local hour. In New York on November 1, 2026, 1:30 a.m. occurs first as EDT (UTC−04:00) and then one hour later as EST (UTC−05:00). The wall-clock label is the same, but the two moments are different.
For software, logs, flights and overnight schedules, store a UTC timestamp or an explicit offset together with a location-specific IANA identifier such as America/New_York, America/Chicago, America/Denver or America/Los_Angeles. A bare “1:30 a.m.” is not enough to identify which occurrence you mean during the repeated hour.
Does DST End on the Same Date Worldwide?
No. November 1, 2026 is the U.S. schedule. Other countries and regions can end daylight saving time on different dates, use different local transition times or not observe DST at all.
If you are coordinating an international meeting, flight or system change, do not assume the U.S. fall-back date is global. Compare the actual named locations for the date you care about.