About Horizon Hour
Horizon Hour publishes sunrise, sunset, twilight, golden hour, blue hour and moon times for cities in North America, Australia and Europe.
How the times are calculated
Every time on this site is computed from the city’s coordinates with Astronomy Engine, an open-source astronomy library. Before publishing we compare our results with the US Naval Observatory; in our checks sunrise, sunset, twilight, moonrise and moonset agreed to within about one minute.
- Sunrise and sunset: the moment the top edge of the sun touches the horizon, including the usual allowance for atmospheric refraction.
- Golden hour: the sun between 4° below and 6° above the horizon. Blue hour: between 6° and 4° below.
- Civil, nautical and astronomical twilight: the sun 6°, 12° and 18° below the horizon.
Times assume a flat horizon at sea level. Mountains, tall buildings and weather can change what you actually see by a few minutes.
Night sky
Planet rise and set times and brightness are calculated the same way. A planet is listed when it is above the horizon between dusk and dawn and far enough from the Sun to be seen. Meteor shower peaks are computed from the solar longitudes in the International Meteor Organization working list, and eclipses are calculated for each city.
Tides
Tide times for US cities are official predictions from NOAA CO-OPS for the nearest prediction station within 15 km. We only show tides where an official prediction station exists; we never estimate tides ourselves. Tide predictions are not for navigation.
City names, coordinates and time zones come from GeoNames (CC BY 4.0).
Who runs this site
Gloden Fan OÜ
Tartu mnt 67/1-13b, Kesklinna linnaosa, 10115 Tallinn, Estonia
Registry code 17343678 · VAT EE102910111
Email: info@glodenfan.com
Found a time that looks wrong? Email us with the city and date and we will check it.