Wake at 5:30 am
Four bedtimes, each one a whole number of sleep cycles before the alarm, with a quarter of an hour allowed for actually falling asleep.
Go to bed at 9:45 pm
5 cycles and 7h 30m asleep: the row nearest eight hours.
| Get into bed | Cycles | Time asleep |
|---|---|---|
| 8:15 pm | 6 cycles | 9h |
| 9:45 pm | 5 cycles | 7h 30m |
| 11:15 pm | 4 cycles | 6h |
| 12:45 am | 3 cycles | 4h 30m |
7h 30m asleep
The night nearest eight hours, laid on a clock face.
The two assumptions
Move either one and every time above moves with it. The settings follow you around the site.
What a 5:30 am alarm asks of the evening
Half past five puts the six-cycle bedtime at 8:15 pm and the five-cycle one at 9:45 pm. Four cycles means 11:15 pm, and three cycles 12:45 am, the only row past midnight.
This is the alarm the twelve-hour day rota on the shift planner produces: a 7:00 am start, less the planner's default hour and a half to get ready, is 5:30 am. Change either figure on the planner and the alarm moves with it.
In London a 5:30 am alarm is in daylight from early May to early August. New York gets about six weeks of it, from late May to early July, and Johannesburg about three months, from the second half of October to the middle of January. In Cape Town sunrise beats 5:30 am for less than three weeks, from late November to the middle of December. Sydney's earliest sunrise of the year is 5:30 am, on 3 October in 2026, the last day before its clocks go forward, so there a 5:30 am alarm meets the sunrise that one morning and is dark on every other.
The six-cycle bedtime of 8:15 pm is before sunset in London from late April to about 20 August, and in New York from late May to the end of July. It is never light at 8:15 pm in Cape Town, Johannesburg or Sydney, whose latest sunsets are 8:01 pm, 7:05 pm and 8:10 pm. The five-cycle bedtime of 9:45 pm is after sunset in all five cities on every day of the year, since London's latest sunset is 9:22 pm.
All four bedtimes fall before the clocks change in the UK, the United States, Europe and Sydney. On the night the clocks go forward, every row is an hour shorter in bed than printed; on the night they go back, an hour longer. The table is exact every night in Johannesburg and Cape Town, which do not change their clocks.
Further afield, Tokyo has daylight at 5:30 am for half the year, from the start of April to late September, and Moscow from the middle of April to the end of August. Delhi's earliest sunrise is 5:23 am, so there the alarm is light from the middle of May to early July, and Dubai manages about four and a half weeks from late May. In Cairo it is light for only about ten days in April, because Egypt puts its clocks forward on the last Friday of that month and sunrise jumps past half past five. São Paulo, which stopped changing its clocks in 2019, has it from the middle of October to the middle of January. Singapore, Mumbai and Madrid never see the sun by 5:30 am. Berlin has the same weeks as London, from early May to early August. Chicago has it from the middle of May to the middle of July, and Beijing from late April to late August. Los Angeles, Toronto, Hong Kong and Auckland are dark at 5:30 am on every day of the year.
Sunrise and sunset: the NOAA solar equations, for each city centre in 2026, to the nearest minute.
Every time on this page comes from two numbers: a cycle of 90 minutes and 15 minutes between getting into bed and being asleep. Neither is a measurement of you. The reference pages say where each one comes from.
A quarter of an hour either way
If the alarm is set to something near but not exactly 5:30 am, the table for it is a page of its own.
The other direction
Already in bed and deciding when to set the alarm? The sleep-now page runs the same sum forwards from the time where you are.