About SunTimeToday

SunTimeToday is a free, open sunrise and sunset calculator built for photographers, outdoor enthusiasts, and anyone who needs accurate solar timing data. Every calculation runs directly in your browser — no servers, no tracking, no sign-ups.

How We Calculate

Our tool uses the SunCalc library, which implements the Jean Meeus astronomical algorithms — the same mathematical models used by NASA and professional astronomers. These algorithms account for Earth's orbital eccentricity, axial tilt, and atmospheric refraction to produce results accurate to within seconds.

When you visit any page on SunTimeToday, the calculations happen entirely on your device. Your latitude and longitude are used locally in JavaScript to compute solar positions. No data is ever sent to a server. We don't collect, store, or transmit your location data.

Why No Server Calls

We chose a fully client-side architecture for two reasons: privacy and speed. Without server round-trips, your results appear instantly. And because your coordinates never leave your device, you can use the tool without worrying about who has access to your location history.

Accuracy

Our sunrise and sunset times are accurate to within ±1 minute for most locations on Earth. Results account for the standard atmospheric refraction angle of 0.833°, which is the accepted value used by the United States Naval Observatory. Real-world accuracy may vary slightly due to local atmospheric conditions, temperature, and pressure.