Daylight
Free online daylight calculator: compute sunrise, sunset, solar noon, and day length for any location worldwide. Includes annual trend charts, city presets, and NOAA-accurate formulas.
About This Calculator
The Daylight Calculator computes sunrise time, sunset time, solar noon, and total daylight hours for any location on Earth on any date. It uses the NOAA-standard solar position algorithm based on Spencer's 1971 formulas, making it suitable for travelers, photographers, astronomers, gardeners, architects, and anyone planning outdoor activities.
The calculation works in three steps. First, the tool determines the solar declination — the Sun's angular distance north or south of the celestial equator — which varies between +23.44° and −23.44° throughout the year due to Earth's axial tilt. Second, it computes the sunrise hour angle using the formula ω₀ = arccos(−tan φ × tan δ), where φ is your latitude and δ is the solar declination. Finally, total daylight is derived as 24 × ω₀ / π hours. The equation of time corrects for Earth's elliptical orbit, ensuring solar noon aligns with your local clock.
The annual trend chart shows how daylight hours change month-by-month at your latitude. At mid-latitudes (e.g., New York 40.7°N), summer days reach about 15 hours while winter days drop to around 9 hours. Near the equator (0°), day length stays close to 12 hours year-round. Above the Arctic Circle, the chart reveals the dramatic transition between Midnight Sun and polar night.
Regional Notes
India: Delhi (28.6°N, 77.2°E, UTC+5.5) — summer days ~14 hours, winter days ~10 hours. The best time for outdoor photography is during the golden hour (approximately 30–60 minutes after sunrise and before sunset).
United States: New York (40.7°N, 74.0°W, UTC−5) — summer days ~15 hours, winter days ~9 hours. Remember to add one hour to the UTC offset during daylight saving time (EDT = UTC−4).
United Kingdom: London (51.5°N, 0.1°W, UTC+0) — summer days ~16.5 hours, winter days ~8 hours. During British Summer Time (BST), use UTC+1. Northern Scotland can experience nearly 18 hours of daylight in June.
Frequently Asked Questions
How does the daylight calculator work?
Enter your latitude, longitude, date, and UTC offset. The tool uses NOAA-style solar equations — including solar declination and the equation of time — to compute sunrise, sunset, solar noon, and total day length for your exact location.
How is day length calculated?
Day length is calculated from the sunrise hour angle ω₀ = arccos(−tan φ × tan δ), where φ is your latitude and δ is the solar declination. Total daylight hours = 24 × ω₀ / π. The solar declination follows Spencer's formula, accurate to within 1 minute for most locations.
Why does day length change throughout the year?
Day length changes because Earth's 23.44° axial tilt causes the Sun's declination to vary between ±23.44° through the year. Around the equinoxes (March and September) day length changes fastest — several minutes per day — while near the solstices (June and December) it barely changes at all.
How accurate is this calculator?
The calculator uses the NOAA solar-position algorithm with Spencer's 1971 formulas for solar declination and equation of time. Results are accurate to within approximately 2 minutes for latitudes between ±66.5° and within 10 minutes for polar regions above ±72° latitude.
What is the best latitude for maximum daylight?
Locations above the Arctic Circle (≈66.5° N) experience Midnight Sun around the June solstice with 24 hours of daylight. Conversely, they have polar night with 0 hours around the December solstice. The equator (0° latitude) gets roughly 12 hours of daylight year-round.
How do I account for daylight saving time?
This calculator uses the standard UTC offset for your time zone. If daylight saving time is in effect, add one hour to the UTC offset. For example, New York (EST, UTC-5) becomes UTC-4 during EDT; London (GMT, UTC+0) becomes UTC+1 during BST.
Does this calculator support cities worldwide?
Yes. You can use the city presets for New York, London, Delhi, Tokyo, Sydney, and Dubai, or enter any custom latitude and longitude from −90° to +90° latitude and −180° to +180° longitude. The calculator works for every location on Earth.
What is solar noon and why does it vary?
Solar noon is when the Sun reaches its highest point in the sky. It rarely occurs at exactly 12:00 PM because of the equation of time (Earth's elliptical orbit) and the difference between your longitude and the time zone's reference meridian. The variation can be up to 16 minutes either side of clock noon.