Day Length Calculator
Total daylight, every twilight band, and whether the days are growing or shrinking — for any date and location, computed in your browser.
Times shown in your local timezone.
40.7128°N, 74.0060°W on 2026-10-08
2026 extremes for this location
Quick Answer
Day length is the time between sunrise and sunset. This calculator shows it for any date and location, plus the three twilight bands (civil −6°, nautical −12°, astronomical −18°), how much daylight changed versus yesterday, and the year's longest and shortest days — all with the NOAA solar algorithm in your browser.
How It Works
Enter your location — search a place, type coordinates, or tap Use My Location
Pick a date; today is preselected
Read day length, all three twilight bands, and the daily trend
Check the year extremes for solstice dates and durations
Key Facts
- Total daylight length in hours and minutes
- Civil, nautical, and astronomical dawn/dusk times
- Day-length change vs yesterday (getting longer or shorter)
- Year's longest and shortest day for your location
- Search by place name or use device location
- Handles polar day and polar night explicitly
- 100% client-side: no uploads, no accounts
Frequently Asked Questions
How many hours of daylight today?
It depends entirely on your latitude and the season. Enter your location above and today's exact daylight duration appears instantly, along with how it compares to yesterday and the year's extremes. At 40° latitude, daylight swings from about 9 hours in December to 15 hours in June; at the equator it stays near 12 hours all year.
What are civil, nautical, and astronomical twilight?
They are brightness bands defined by how far the sun is below the horizon. Civil twilight (0° to −6°) is when there is still enough light for most outdoor activities — streetlights on, horizon visible. Nautical twilight (−6° to −12°) is when sailors can still see the horizon while stars are visible. Astronomical twilight (−12° to −18°) is when the sky still has a faint glow; beyond it comes true darkness.
Are the days getting longer or shorter?
The calculator compares today's daylight with yesterday's and reports the per-day change. Around the solstices (≈June 21 and ≈December 21) the change is nearly zero; it peaks near the equinoxes (≈March 20 and ≈September 22), when mid-latitude locations gain or lose 2–4 minutes of daylight per day.
What is the longest day of the year?
For the Northern Hemisphere it falls around June 20–22 (the June solstice); for the Southern Hemisphere around December 21–22. The calculator scans your chosen year for your exact location and reports both the longest and shortest day with their dates and durations.