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Sunrise & Sunset Time

Get sunrise, sunset, solar noon, day length and civil / nautical / astronomical twilights for any city or coordinates on any date. NOAA Solar Position Algorithm runs offline; city search uses the open-source Open-Meteo geocoder. Free and private.

What is the Sunrise & Sunset Time?

A sunrise/sunset calculator finds when the sun rises, when it sets, when it's at its highest point and the durations of the three twilight bands for a given (latitude, longitude, date). Toollyz Sunrise & Sunset Time implements NOAA's Solar Position Algorithm directly in the browser — the same equations used by gml.noaa.gov/grad/solcalc — so the solar math is offline and entirely client-side. Pick a location by searching a city (we call the open-source Open-Meteo geocoder directly from your browser, no Toollyz server in the path) or by typing latitude and longitude. The hero shows sunrise, solar noon and sunset in the location's timezone with the UTC time underneath, plus the day length in `Xh Ym Zs`. The twilight panel lists civil (sun 6° below the horizon — "streetlights start"), nautical (12° — "horizon barely visible") and astronomical (18° — "true astronomical darkness") dawns and dusks. At high latitudes the algorithm detects polar day and polar night and surfaces a banner explaining why some events are blank. Refraction is included via the official 90.833° zenith — results are accurate to ±1 minute for typical latitudes.

How to use it

  1. Search for a city (or paste latitude / longitude) and pick a date.
  2. Watch the sunrise / solar noon / sunset cards populate, with the day-length line below.
  3. Scroll to the Twilights panel for civil / nautical / astronomical dawn and dusk.
  4. Tap My location to pull your current coordinates via the browser's Geolocation API.

Benefits

  • NOAA Solar Position Algorithm — accurate to ±1 minute for typical latitudes.
  • Times displayed in the location's IANA timezone with UTC under each one.
  • Civil / nautical / astronomical twilight bands, each with dawn and dusk times.
  • Polar-day / polar-night detection — explicit banner instead of "00:00" placeholders.
  • Open-Meteo geocoder for city search — browser-side direct, no Toollyz server.
  • Browser Geolocation API for My location with explicit user-permission prompt.
  • Day length displayed in hours, minutes and seconds.
  • 100% private — solar math runs offline, only city lookups touch the network.

Frequently asked questions

How accurate are the times?

Within about ±1 minute for typical latitudes (40°N–40°S). At very high latitudes near the polar circles, the algorithm becomes more sensitive to small altitude and refraction effects and the error can grow to a few minutes. For sub-second astronomical precision, use a dedicated tool with the more elaborate SPA from NREL.

Does the solar math need an internet connection?

No — the NOAA Solar Position Algorithm runs entirely in your browser using `Math.sin` / `Math.cos`. Only the city search requires a connection; once you have coordinates, switching dates is fully offline.

Which geocoder do you use?

Open-Meteo (`https://geocoding-api.open-meteo.com`). It's free, requires no API key, supports CORS and ships with 200k+ cities. Your browser calls it directly; Toollyz has no server in the path.

What are civil, nautical and astronomical twilight?

Civil twilight is when the sun is 6° below the horizon — bright enough for most outdoor activities without artificial light. Nautical is when the sun is 12° below — the horizon is barely visible at sea. Astronomical is when the sun is 18° below — the sky is truly dark and astronomers can observe faint objects.

Why is everything blank for some dates?

At high latitudes (above the Arctic / Antarctic circles), there are days when the sun never rises or never sets — polar day and polar night. The calculator detects this and shows a banner explaining what's happening instead of bogus times.

What timezone do I see the times in?

The location's IANA timezone (e.g. America/New_York). The UTC time is shown underneath each card so you can cross-check or convert manually. The date input is interpreted as local-date in the location's timezone for consistency.

Does altitude affect the results?

Slightly — the official zenith already includes a small refraction correction for sea level. At significant elevation (>500 m) sunrise comes a minute or two earlier than the default and sunset is correspondingly later. Toollyz doesn't accept altitude in this release.

Can I see times for tomorrow / yesterday?

Yes — pick any date in the date input. The algorithm works for any year from ~1900 to ~2100 with the rated accuracy; it's more imprecise outside that range but still usable.

Are my coordinates uploaded?

Only when you click Search (the city name goes to Open-Meteo) or use My location (the browser asks for permission to share GPS coordinates with the page, which Toollyz then uses locally). Toollyz has no server, so coordinates never reach us.

Is this Sunrise & Sunset tool free?

Completely free with no signup and no limits. Look up as many cities and dates as you like — privately in your browser.

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