What are daylight hours?

Daylight hours measure the time between sunrise and sunset on a given day at a specific location. The length of the day depends on three factors: your latitude, the date, and Earth's axial tilt of about 23.5°. Because of this tilt, the Sun's apparent path across the sky changes throughout the year, making summer days longer and winter days shorter outside the tropics.

Near the equator, days stay close to 12 hours all year. The further you move toward the poles, the more dramatic the seasonal swing becomes — until you reach the polar circles, where the Sun can stay above the horizon for 24 hours (midnight sun) or below it for 24 hours (polar night). The longest day of the year is the summer solstice, the shortest is the winter solstice, and the equinoxes mark the two days when daylight and night are roughly equal everywhere on Earth.

Knowing the exact length of the day is useful in photography, agriculture, solar energy planning, sleep and circadian-rhythm research, outdoor activity planning, and many scientific calculations.

Tool description

This calculator tells you exactly how many hours of daylight a given day has at any location on Earth. Enter (or auto-detect) a latitude and longitude, pick a date and timezone, and the tool computes sunrise, sunset, solar noon, and the total length of the day as a human-readable duration. Night length is shown as well.

Examples

London, UK on the summer solstice (2026-06-21):

  • Sunrise: 04:43
  • Sunset: 21:21
  • Daylight duration: 16h 38m

Tromsø, Norway on the winter solstice (2026-12-21):

  • The Sun does not rise — polar night
  • Daylight duration: 0
  • Night duration: 24h

Quito, Ecuador on the equinox (2026-03-20):

  • Sunrise: 06:18
  • Sunset: 18:24
  • Daylight duration: 12h 6m

Features

  • Automatic geolocation with optional manual latitude/longitude input
  • Date and timezone selectors for precise results anywhere in the world
  • Human-readable daylight and night duration (e.g. "13h 42m")
  • Sunrise, sunset, and solar noon timestamps
  • Polar day and polar night detection for high-latitude locations

Use cases

  • Photographers and filmmakers planning outdoor shoots and figuring out how much usable daylight a day offers.
  • Solar energy estimation — quickly check effective sunlight time for a panel installation or off-grid system.
  • Travel and outdoor activity planning — hikers, anglers, and trip planners use day length to schedule activities safely.

How it works

The tool uses the SunCalc library, which implements astronomical formulas based on the Sun's position relative to Earth. For a given date and geographic coordinates, SunCalc computes when the upper edge of the Sun crosses the horizon (sunrise and sunset). The daylight duration is simply the difference between sunset and sunrise, expressed in milliseconds and converted to decimal hours and a human-friendly format.

Solar noon — the moment the Sun reaches its highest point in the sky — is also calculated and shown. All times are converted to the timezone you select, so they match local clocks rather than UTC.

Options explained

  • Manual input: Disable browser geolocation and enter latitude and longitude by hand. Useful for planning trips or checking remote locations.
  • Latitude / Longitude: Coordinates in decimal degrees. Latitude must be between −90 and 90, longitude between −180 and 180.
  • Date: The day to calculate daylight for.
  • Timezone: Output timestamps are formatted in this timezone. Defaults to your browser's detected timezone.

Limitations

  • Results are based on geometric sunrise/sunset (the Sun's center crossing a slightly refraction-corrected horizon) and assume a flat horizon. Mountains, tall buildings, and atmospheric conditions can shift the actual visible sunrise/sunset by several minutes.
  • Above the Arctic Circle (66.5° N) and below the Antarctic Circle (66.5° S), the Sun can stay continuously above or below the horizon for days or months. The tool reports this as a polar day or polar night.
  • Daylight length differs from "useful light" — civil, nautical, and astronomical twilight extend usable light beyond pure sunrise and sunset.

Tips

  • For photography, combine the daylight hours with the Golden hour finder and Sunrise calculator to plan the best lighting windows.
  • Compare two cities by running the calculator twice with the same date — useful for travel planning across different latitudes.
  • Combine sunrise and sunset timestamps with the daylight duration for spreadsheets and solar-yield estimates.

FAQ

Why is my day length slightly different from what my weather app shows? Different sources use slightly different definitions of sunrise/sunset (top vs. center of the Sun, refraction model, horizon altitude). Differences of 1–3 minutes are normal.

Does the tool account for daylight saving time? Yes. Times are formatted in the selected timezone, which automatically applies DST rules where applicable.

What happens at the poles? If the Sun never rises or never sets on that date, the tool shows a polar day / polar night message instead of timestamps.

Can I use this for any historical or future date? Yes. SunCalc works for any date supported by JavaScript's Date object, which spans roughly ±275,000 years from 1970.