What the golden hour is
The golden hour is the time around sunrise and sunset in which the sun stands low and the light is warm and soft. The blue hour is the twilight shortly before the golden hour of the morning and shortly after that of the evening, when the sky turns deep blue. Both are defined by the height of the sun above the horizon, so their length depends on place and season.
There is no standard definition. This calculator uses the altitude of the centre of the sun: the golden hour lasts while the sun is between -4° and +6°, the blue hour while it is between -6° and -4°. Sunrise and sunset are the times at -0.833°, and the twilight times use the usual limits of -6°, -12° and -18°.
| Phase | Altitude of the sun |
|---|---|
| Golden hour | -4° … +6° |
| Blue hour | -6° … -4° |
| Civil twilight | −6° |
| Nautical twilight | −12° |
| Astronomical twilight | −18° |
| Sunrise / Sunset | -0.833° |
The altitudes are geometric, without atmospheric refraction. For sunrise and sunset, -0.833° is the value that the NOAA calculator assumes for the refraction at the horizon. The twilight limits are those of the NOAA glossary.
How the times are calculated
The position of the sun is calculated with the equations of the NOAA Solar Calculator, which are based on Jean Meeus, Astronomical Algorithms. For each day the program follows the altitude of the sun through the local day and finds the moments at which it crosses the limits above. This works the same way in every time zone and in polar regions.
NOAA states that sunrise and sunset are theoretically accurate to within a minute for latitudes between 72° north and 72° south and to within 10 minutes beyond. The times of this tool were checked against the NOAA sunrise tables for several places and dates and agree to about a minute.
Limits of the calculation
The times assume a flat horizon at sea level. Air pressure, temperature and humidity change the refraction, and mountains, buildings or trees hide the sun earlier than the calculated horizon. The golden light also changes gradually, so the start and end of the phases are not sharp.
Weather decides how much of the light arrives. The times follow the daylight saving time of the place on the chosen date, as known to the time zone database of the browser. Dates before 1900 and after 2100 are not offered. For a place that is not in the list, coordinates can be entered; the time zone of the nearest listed place is used then.
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Frequently asked questions
What time is the golden hour?
It depends on place and date. Here it is the time in which the sun stands between -4° and +6° above the horizon: in the morning from just before sunrise until the sun has risen to 6°, in the evening from 6° until just after sunset. The calculator shows the exact times for the chosen place and date.
What is the difference between the golden hour and the blue hour?
The golden hour is centred on sunrise and sunset, with the sun low at the horizon. The blue hour lies outside it, before the morning and after the evening golden hour, while the sun is between -6° and -4° and the sky glows blue.
Does the golden hour last one hour?
Not exactly. Its length depends on latitude and season, and the calculator shows it in minutes. Near the equator the sun rises and sets steeply, so the phase is short. At higher latitudes it takes longer.
How accurate are the times?
NOAA gives an accuracy of about one minute for sunrise and sunset between 72° north and 72° south. Real times vary with the weather and with the horizon. The phases of the golden and blue hour have no sharp edges, so a few minutes of difference do not matter in practice.
Why is there no golden hour on some days?
Near the poles the sun can stay above the golden hour range all day (polar day) or below it (polar night). Then the phase is missing on that date, or the sun stays in the range for hours and the tool shows one long stretch around noon.
Sources
- NOAA Global Monitoring Laboratory: Solar Calculator: Calculation Details (equations, refraction, accuracy). https://gml.noaa.gov/grad/solcalc/calcdetails.html
- NOAA Global Monitoring Laboratory: Solar Calculator Glossary (definitions of civil, nautical and astronomical twilight). https://gml.noaa.gov/grad/solcalc/glossary.html
- GeoNames: Place data (cities with more than 15,000 inhabitants), licence CC BY 4.0. https://www.geonames.org/
- NOAA Global Monitoring Laboratory: Solar Calculator: sunrise, sunset and solar noon tables (reference values for the test). https://gml.noaa.gov/grad/solcalc/table.php