How long is a day? There are two different answers, and mixing them up causes confusion. A calendar day is always 24 hours — but the daylight part (sunrise to sunset) changes constantly with your latitude and the season. Here's the difference.
To see today's daylight hours for your city, use the [sun page](/sun).
A day vs daylight
- A day = 24 hours — one full rotation of Earth. This never changes (apart from the leap second, which is a tiny correction).
- Daylight / day length = the time between sunrise and sunset — the hours the Sun is above the horizon. This varies a lot.
So "the days are getting longer" really means daylight is getting longer — the 24-hour day stays the same.
How daylight hours change
Daylight length depends on latitude and season:
| Location | Shortest day | Longest day |
|---|---|---|
| Equator | ~12 hours | ~12 hours (barely changes) |
| London (51°N) | ~8 hours | ~16.5 hours |
| Stockholm (59°N) | ~6 hours | ~18.5 hours |
| Inside Arctic Circle | 0 hours (polar night) | 24 hours (midnight sun) |
The closer to the poles, the more extreme the swing. At the equator, daylight stays near 12 hours all year.
The solstices and equinoxes
- [Summer solstice](/blog/longest-day-of-the-year-2026-summer-solstice) — the longest daylight of the year.
- [Winter solstice](/blog/shortest-day-of-the-year-winter-solstice-2026) — the shortest.
- Equinoxes (March & September) — day and night nearly equal (~12 hours) everywhere.
Quick answers
How long is a day? A calendar day is 24 hours. Daylight (sunrise to sunset) varies from 0 to 24 hours depending on latitude and season.
Why do daylight hours change but the day stays 24 hours? The 24-hour day is one Earth rotation; daylight is just the portion when the Sun is up, which shifts with Earth's tilt through the year.
Where does daylight not change? At the equator, daylight stays close to 12 hours all year.
When is day and night equal? At the equinoxes, around 20 March and 22–23 September.