How the sun times are calculated
The times come from the same family of equations NOAA publishes for sunrise, sunset and solar noon: the sun’s geometric mean longitude and anomaly, the equation of time, the declination, and an hour angle for a chosen altitude. Official sunrise uses a zenith of 90.833° to allow for refraction and the sun’s radius. Golden and blue windows use altitudes of 6° and −6° as explained on those pages.
Your city is looked up from a short list with a latitude, a longitude and an IANA time zone, so daylight saving is applied by the browser. The page does not call a weather or sun API. Expect the result to be within a couple of minutes of a well-known calculator in clear conditions; hills, weather and the exact official definition of “sunset” at a given harbour or airport can still differ. Figures and definitions checked 12 November 2026.