FLIGHTS BOOKED ACROSS A CLOCK CHANGE
My flight crosses the night the clocks change
The ticket says a departure time and an arrival time. One of them is in a different offset from the other, and the duration in between is not what subtraction suggests.
You look at the ticket. Depart 22:40, arrive 06:15. You do the subtraction, get seven hours thirty-five, and think: that seems short.
It is short. The clocks changed while you were in the air, and the flight is actually eight and a half hours.
Why the arithmetic fails
Both times on a ticket are local times at their own airports. That is the right convention — it is what you need to plan around at each end — but it means you cannot subtract them to get a duration unless both ends are in the same offset, which on an international flight they never are.
On a normal night you can correct for it by adding the zone gap. On the night the clocks change, the gap itself moves mid-flight, so even that correction is wrong unless you know which side changed and when.
What actually happens on board
Nothing. Aviation runs on UTC — flight plans, air traffic control, crew duty limits, the aircraft's own clocks. UTC has no daylight saving and no transitions, so from the operational side the night the clocks change is an ordinary night.
The change exists only at the two ends, where local civil time is printed on your ticket and displayed in the terminal.
The things that genuinely catch people
Ground transport at the arrival end. The 05:30 train that you booked exists on a normal morning. On the spring-forward morning, the hour between 02:00 and 03:00 does not happen, and some early services are cancelled or retimed. This is where people actually get stranded.
Connections with short layovers. A 55-minute connection is fine until one leg's local schedule shifts relative to the other's.
Your alarm on the departure morning. If you are flying out on the morning after the change, a phone set to the correct zone handles it and a hotel wake-up call sometimes does not.
Your own body. The clock change is an hour on top of however many zones you just crossed, in whichever direction. Landing after an eastward red-eye on the spring-forward morning is the worst combination available.
What to actually do
Trust the ticket's local times, not your subtraction. Those two numbers are correct. The duration you computed from them is not.
Check ground transport separately for the arrival morning, especially if it is the spring transition. Timetables for that night are published but not always prominent.
Give yourself a longer connection than you normally would, if the itinerary crosses a transition. This is a night to have slack.
Do not adjust anything manually. Phones handle it correctly. Every problem in this category comes from someone helpfully "fixing" a time that was already right.
The dates
This year: 2026-03-08 and 2026-11-01 in the US, 2026-03-29 and 2026-10-25 in the UK and EU. In Australia, 2026-04-04 and 2026-10-03.
If you are booking a flight for one of those nights, it is worth knowing before you choose the connection rather than after.
Related: I land before I took off · The clock change: what happens at 2am
Timezone: World Clock Widget
A world clock, converter and live day/night map for iPhone — 325 cities, offline, no account.
Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.