Daylight Hours Calculator
Pick a date and set your latitude - 40 is about the US average. The calculator runs the sun geometry and returns the day length, the longest and shortest days at your latitude, and how many minutes a day you are gaining or losing right now.
Sunrise-sunset tables bury the number people actually want: how much light the day holds, and how fast it is leaving. This one answers that - and says the quiet part about under-ten-hour days: the best-evidenced fix for the winter blues is morning outdoor light, not the desk lamp.
How to use
- Set the date you are curious about - today is preloaded.
- Set latitude: about 40 for the US mid-band, 51 for London, 66 is the Arctic Circle.
- Watch the per-day change flip sign at the solstices.
Frequently asked questions
How many hours of daylight in winter?
It depends almost entirely on latitude: at 40 degrees north the shortest day runs about 9 hours 20 minutes; at 50 degrees (Frankfurt, Winnipeg edges) it drops under 8; inside the Arctic Circle the sun never rises. The calculator gives your exact figure.
How fast do we lose daylight in fall?
The steepest losses sit near the equinox - around 3 minutes a day at 40 degrees north, faster the further north you go - slowing to zero at the solstice. Daily it is invisible; over October it adds up to nearly an hour and a half.
Does daylight saving time change daylight hours?
No - it moves an hour of light from morning to evening (or back). The sun gives the same day length either way; only the clock labels shift. That is why the sleep-shift plan and the daylight math are separate questions.
Why is my sunrise table a few minutes off this result?
Day length as computed here uses pure geometry; real sunrise tables add atmospheric refraction and the solar disc radius, stretching the day by several minutes at the edges. For planning your daylight, the geometry is the honest middle.