London to New York
The clock moves whether or not you are ready for it. This works out by how much, and what a bedtime walked an hour a night would look like on the way there or once you arrive.
New York runs 5 hours behind London. To arrive already keeping New York hours, your bedtime has to move 5 hours later — from 10:00 pm to 3:00 am, on your own clock at home. That is 5 nights, so the table below starts 5 nights before you fly.
| Night | Bed | Up | Moved | Sunset there on this clock | Sunrise there on this clock |
|---|---|---|---|---|---|
| Night 1 | 11:00 pm | 7:30 am | +1h | 11:53 pm | 11:45 am |
| Night 2 | 12:00 am | 8:30 am | +2h | 11:51 pm | 11:46 am |
| Night 3 | 1:00 am | 9:30 am | +3h | 11:50 pm | 11:47 am |
| Night 4 | 2:00 am | 10:30 am | +4h | 11:48 pm | 11:48 am |
| Night 5 | 3:00 am | 11:30 am | +5h | 11:46 pm | 11:49 am |
The gap
New York runs 5 hours behind London for most of the year. Both ends put their clocks forward for their summer and back for their winter, but not on the same dates, so in the days between the two changes the gap is an hour different. The planner above works from the difference on the date in its field, so for a trip in those days its figure is the one that applies.
What that asks of a bedtime
Taking the shorter way round the dial, the move is 5 hours later. At the planner's usual step of an hour a night, that is 5 nights of shifting, either before you fly or after you land.
This is clock arithmetic and nothing else. It does not know how you sleep on aeroplanes, it makes no claim about how quickly anybody adjusts, and an hour a night is a step size rather than a finding. Shorten the step in the planner if a smaller one suits you.
London to New York through the year
London to New York is a move of five hours back, and for four weeks of the year, four. Britain and the United States both put their clocks forward in spring, but on different Sundays: the United States on the second Sunday of March and Britain on the last, so for about three weeks in March the gap is four hours. In autumn the order is the same. Britain goes back on the last Sunday of October and the United States a week later, on the first Sunday of November, which gives one more week at four hours.
By the sun, New York is about four hours and fifty-six minutes behind London, since it sits 74 degrees further west, so the five-hour figure is the one that matches the daylight. The two cities are about 5,570 km apart on the great circle.
Going west, the move is later. A 10:00 pm bedtime in London is 5:00 pm in New York for most of the year, and at an hour a night that is five nights of shifting, or four in the shoulder weeks. Before you fly, the plan ends at 3:00 am London time on the last night, which is 10:00 pm in New York. After you land, the first night's bedtime is 6:00 pm local time, and each night after it an hour later.
The two cities share a calendar date except between midnight and 5:00 am in London, when New York is still on the day before. New York's summer sunsets come as late as 8:31 pm, which is 1:31 am in London.
Going back
The return leg has its own page: New York to London.
Once you are there
With the clocks settled, the ordinary question comes back: what time to go to bed for the alarm you have set. That is the wake-time pages, which count in cycles rather than in zones.