Daylight hours
How long is today?
Pick a city, then drag along the year. The curve is every day’s daylight from January to December, and the dashed line is the day you are looking at.
Today
0h 0m
Reading the curve
- The peak is the longest day of the year for that city, at the June solstice in the northern hemisphere and the December solstice in the southern.
- The steepest parts are around the equinoxes in March and September. That is when day length changes fastest, which is why spring evenings seem to stretch so quickly.
- A flat curve means a city near the equator, where day length barely moves all year. Try Singapore or Nairobi, then Stockholm.
What counts as daylight here
Daylight is the time between sunrise and sunset, measured to the Sun’s upper edge on a flat sea-level horizon with standard atmospheric refraction. Twilight before sunrise and after sunset is extra, usable light that is not counted. Terrain and buildings will shorten what you actually see.
Calculated in your browser with the NOAA solar position equations for the current year. Expect agreement with almanac times to within a minute or two for these cities.
Make the most of the light you have
Know where the Sun will set tonight.
Asterfold is a sunset planner for iPhone. A sky dome draws the Sun’s real path for any place and date, coloured by golden hour, blue hour and twilight, with the year’s range of sunset and sunrise directions around the rim.
Save the spot you watch from, aim your view, and see the dates this year when the Sun sets inside your frame. Calculated on your iPhone, so it works offline.
Get Asterfold on the App StoreFree: the Studio, aiming and plans for 2 viewpoints, the journal, tonight’s ratings and the next 3 evenings. Asterfold Plus is an optional upgrade. No account. Requires iOS 18 or later. Details checked against the App Store listing on November 10, 2026.
Publisher disclosure: Honest Little Apps publishes both Asterfold and this page. This is not an independent review. This page is a separate web companion, not a feature of the app. This calculator is not a feature of the app. Sun positions assume a flat horizon; hills, buildings and trees are not modelled.
Questions
How many hours of daylight are there today?
Choose your city above and the page shows today’s hours and minutes of daylight, with sunrise and sunset times, and how much it has changed since yesterday.
When is the longest day of the year?
At the June solstice in the northern hemisphere and the December solstice in the southern hemisphere. The page shows the date and length for the city you pick.
When do the days change fastest?
Around the March and September equinoxes. Near the solstices the change slows to seconds a day.
Does daylight include twilight?
No. It runs from sunrise to sunset. There is usable light for a while before sunrise and after sunset that is not counted here.
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