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Daylight duration calculator

Daylight hours vary dramatically with latitude and season. Enter your latitude to get monthly daylight averages for a full year, or a day-by-day breakdown for any date range, plus.

About this calculator

How daylight varies by latitude

LatitudeSummer solsticeWinter solsticeEquinox
0° (equator)~12h~12h~12h
23.5° (tropics)~13.5h~10.5h~12h
40° (mid-latitudes)~15h~9.5h~12h
66.5° (Arctic Circle)~24h (polar day)~0h (polar night)~12h
90° (North Pole)~24h (6 months)~0h (6 months)~12h

Solstices and equinoxes

The calculator finds these automatically by scanning each day of the year:

  • Summer solstice (N. hemisphere) — the day with the most daylight, around June 21
  • Winter solstice (N. hemisphere) — the day with the least daylight, around December 21
  • Spring and fall equinoxes — the days when daylight is closest to 12 hours, around March 20 and September 22

For the southern hemisphere, summer and winter are swapped.

Worked example

Latitude 40° N, 2026 — June (summer)

Average June daylight: approximately 14.8h. Longest day (June 21): approximately 15.0h. Shortest day in June (June 1 or 30): approximately 14.6h.

Notes

  • Monthly averages are rounded to one decimal place.
  • Date range mode is capped at 366 rows for browser performance.
  • All times are UTC-meridian (longitude 0) calculations; local clock time depends on your time zone.

Frequently asked

How is daylight duration calculated?
The calculator uses the NOAA solar algorithm to find sunrise and sunset times at the given latitude (with longitude fixed at 0 for UTC). The difference between sunset and sunrise minutes gives the daylight duration for each day.
Why is longitude fixed at 0?
Longitude shifts the clock time of sunrise and sunset but does not change the total duration of daylight for a given latitude and date. Fixing longitude at 0 gives accurate daylight durations regardless of where you are in a time zone.
What are polar day and night?
Above the Arctic Circle (about 66.5° N) or below the Antarctic Circle (66.5° S), the sun may remain above the horizon for an entire 24-hour period (polar day) or below the horizon all day (polar night) near the solstices. The calculator reports 24h or 0h for these conditions.
How accurate are the solstice and equinox dates?
The dates are approximate, found by scanning each day of the year for the maximum, minimum, and ~12-hour daylight points. They are accurate to within 1–2 days for practical purposes.
Does daylight saving time affect the results?
No. The calculator reports raw solar daylight duration, which is independent of clock time and daylight saving time adjustments.
How do I use the date range mode?
Switch to "Date range," enter a start and end date, and the calculator shows a day-by-day table of daylight hours, sunrise, and sunset times for the chosen latitude.

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