How are hours of daylight calculated?

Daylight is the time from sunrise to sunset. The calculator finds the Sun's declination for the date, then the hour angle H at which the Sun's centre is 0.833° below the horizon: cos H = cos(90.833°)/(cos φ cos δ) − tan φ tan δ. Day length = 2H/15 hours. This is the method of the NOAA solar calculator.

Are sunrise and sunset shown in my local time?

Yes, when you give a longitude and UTC offset. City presets and "Use my location" set the time zone automatically, including daylight saving time on the chosen date. Solar noon depends on longitude and the equation of time, so it is rarely exactly 12:00.

What is the difference between civil, nautical and astronomical twilight?

Civil twilight lasts until the Sun is 6° below the horizon; there is enough light for most outdoor activities. Nautical twilight runs to 12° (the horizon is still visible at sea) and astronomical twilight to 18°, after which the sky is fully dark. The tool lists the dawn and dusk time for each.

Why is daylight at the equator slightly longer than 12 hours?

Sunrise and sunset are defined by the top edge of the Sun touching an horizon that refraction lifts by about 34 arcminutes. Together with the 16-arcminute solar radius this adds about 3.5 minutes at each end, so the equator gets about 12 hours 7 minutes of daylight every day.

Which day has the most and least daylight?

In the Northern Hemisphere the longest day is the June solstice (about June 21) and the shortest is the December solstice (about December 21); the Southern Hemisphere is the reverse. At 40° N that is about 15 h 01 m versus 9 h 19 m.

How fast does day length change?

Fastest near the equinoxes and almost zero at the solstices. At 40° N days change by about 2 minutes 40 seconds per day in March and September; at 60° N it is about 5 minutes 30 seconds per day. The "vs. previous day" figure shows the change for your date.

What happens near the poles?

Above about 66.5° latitude the Sun can stay up all day around the summer solstice (midnight sun, 24 h daylight) or stay below the horizon around the winter solstice (polar night, 0 h). The calculator reports these cases and still shows twilight where it occurs.

How accurate are the times?

The NOAA equations are accurate to about a minute for dates between 1800 and 2100 at latitudes below about 72°. Terrain, elevation and unusual refraction can shift the sunrise or sunset you actually see by a few minutes.

Daylight Hours Calculator

Enter a location and date to get hours of daylight, local sunrise and sunset, solar noon, the three twilight phases, the change from the previous day and a month-by-month table. Uses the NOAA solar position equations.

Daylight Calculator

Latitude

Longitude

Decimal degrees. North and East positive; South and West negative.

Date

UTC offset (h)

Quick presets

Enter a location and date, then press Calculate.

Total Daylight

Sunrise

Sunset

Details

Location

Date

Solar noon

Equation of time

Solar declination

Hour angle at sunrise

Night length

Civil light (dawn to dusk)

Twilight

Phase (Sun below horizon)	Dawn	Dusk	Light span
Civil (6°)
Nautical (12°)
Astronomical (18°)

Daylight vs. Night

Daylight Night

Through the year at this location (21st of each month)

Date	Sunrise	Sunset	Daylight

Hours of daylight by latitude at the equinoxes and solstices

Sunrise to sunset (90.833° zenith), 2026 dates, NOAA equations. For the Southern Hemisphere read the June and December columns the other way round.

Latitude	Mar 20, 2026	Jun 21, 2026	Sep 23, 2026	Dec 21, 2026
0° N	12h 07m	12h 07m	12h 07m	12h 07m
10° N	12h 07m	12h 42m	12h 06m	11h 32m
20° N	12h 07m	13h 20m	12h 07m	10h 55m
30° N	12h 07m	14h 05m	12h 07m	10h 13m
40° N	12h 08m	15h 01m	12h 07m	9h 19m
50° N	12h 10m	16h 22m	12h 09m	8h 04m
60° N	12h 13m	18h 52m	12h 11m	5h 52m
65° N	12h 15m	22h 02m	12h 12m	3h 35m
70° N	12h 19m	24h 00m (midnight sun)	12h 15m	0h 00m (polar night)

Method and worked example

The calculator follows the NOAA Global Monitoring Laboratory solar calculator, which implements Jean Meeus' Astronomical Algorithms. For each date it evaluates the Julian century T at local noon, the Sun's mean longitude and anomaly, the equation of centre, the apparent longitude and the corrected obliquity of the ecliptic, giving the declination δ and the equation of time.

New York (40.7128° N, 74.006° W), June 21, 2026, UTC−4 (EDT): δ = 23.44°, equation of time = −1.9 min.
cos H = cos 90.833° / (cos 40.71° · cos 23.44°) − tan 40.71° · tan 23.44° = −0.3939, so H = 113.20°.
Day length = 2 × 113.20 / 15 = 15.09 h = 15 h 06 m.
Solar noon = 720 − 4 × (−74.006) − (−1.9) − 240 = 777.9 min = 12:58 PM; sunrise = solar noon − 4 × 113.20 min = 5:25 AM, sunset = 8:31 PM.

Twilight uses the same hour-angle equation with zenith 96° (civil), 102° (nautical) and 108° (astronomical). If cos H is below −1 the Sun never reaches that depression (24 h daylight or continuous twilight); above +1 it never rises that high.

Privacy: everything runs in your browser. "Use my location" reads coordinates from your device and sends them nowhere.

Summary

This daylight hours calculator finds how long the Sun is above the horizon on any date at any place on Earth. It uses the NOAA solar calculator equations (from Meeus, Astronomical Algorithms) for solar declination and the equation of time, then solves the sunrise hour angle for a 90.833° zenith, which includes 0.833° for atmospheric refraction and the Sun's radius. With longitude and a UTC offset it converts the result to local clock times for sunrise, sunset and solar noon, and it repeats the calculation at 96°, 102° and 108° for civil, nautical and astronomical twilight. A month-by-month table shows how day length changes through the year at your location, and the reference table below gives day length by latitude at the equinoxes and solstices.

How it works

Pick a city preset or enter latitude and longitude in decimal degrees (north and east positive), or use your device location.
Pick a date. The UTC offset follows the preset's time zone, including daylight saving time; you can type any offset instead.
The tool computes the Julian century, the Sun's apparent longitude, declination δ and the equation of time with the NOAA equations.
Sunrise hour angle: cos H = cos(90.833°)/(cos φ cos δ) − tan φ tan δ. Day length = 2H/15 hours.
Solar noon (minutes) = 720 − 4 × longitude − equation of time + 60 × UTC offset; sunrise and sunset are solar noon ∓ 4H minutes.
Twilight times use the same formula with the Sun 6°, 12° and 18° below the horizon (zenith 96°, 102°, 108°).

Use cases

Check how many hours of daylight a winter trip to Iceland, Norway or Alaska will have.
Find sunrise and sunset times for a hike, ski day or road trip.
Plan photography around civil twilight (blue hour) and astronomical darkness for stargazing.
Compare day length across latitudes at the solstices and equinoxes.
Track how fast days are getting longer or shorter around the equinoxes.
Estimate daylight for gardening, poultry lighting or off-grid solar planning.
See when midnight sun and polar night begin at high latitudes.

Frequently Asked Questions

Last updated: 2026-10-09 · Reviewed by Nham Vu