SunreachExplainers · Updated
How to calculate golden hour: times by latitude and season
To calculate golden hour, find the times when the sun's centre is 4° below and 6° above the horizon, using a solar position algorithm such as NOAA's for your latitude, longitude and date. In Ljubljana on 21 December 2027 that gives 07:19–08:31 and 15:28–16:40.
Sunreach is a 3D and AR sun tracker for iPhone and iPad, coming soon to the App Store. This guide describes the current app; planned upgrades are listed separately. Terrain coverage varies by location.
What is the formula for golden hour?
Golden hour starts or ends when the sun's true altitude reaches −4° or +6°. The altitude comes from sin(alt) = sin φ · sin δ + cos φ · cos δ · cos H, with φ the latitude, δ the sun's declination and H the hour angle.
Declination and hour angle follow from the date and time through the solar equations in Jean Meeus' Astronomical Algorithms, which the NOAA Solar Calculator implements (accurate to about 0.01°). Step through the day, note where the altitude crosses −4° and +6°, and convert to local time in the place's time zone. Sunreach does exactly this every 30 seconds and interpolates the crossing. Blue hour is the same with −6° and −4°.
There is no single official definition. Some calculators use 0° to +6° (sunrise to 6°), some −4° to +6°; the start can differ by about 20 minutes between apps for that reason alone.
When is golden hour in the morning?
Around sunrise, starting 20–25 minutes before it at mid-latitudes. On 21 December morning golden hour in Ljubljana is 07:19–08:31 (sunrise 07:41).
Morning golden hour (−4° to +6°), flat horizon, local time:
| Morning | 20 Mar | 21 Jun | 23 Sep | 21 Dec |
|---|---|---|---|---|
| Singapore | 06:56–07:36 | 06:47–07:30 | 06:41–07:21 | 06:47–07:31 |
| Los Angeles | 06:41–07:30 | 05:24–06:19 | 06:26–07:15 | 06:37–07:33 |
| Ljubljana | 05:48–06:45 | 04:48–05:57 | 06:31–07:29 | 07:19–08:31 |
| London | 05:44–06:48 | 04:15–05:37 | 06:27–07:32 | 07:38–09:05 |
| Oslo | 05:54–07:14 | 03:02–05:13 | 06:37–07:58 | 08:41–11:24 |
| Reykjavík | 07:00–08:32 | until 04:52, from the night before | 06:44–08:16 | 10:30–16:22 (one band all day) |
Sunreach computes this for any spot on Earth, from the real terrain around it. Get the app ↓
When is golden hour in the evening?
Around sunset, ending 20–25 minutes after it at mid-latitudes. On 21 December evening golden hour in Ljubljana is 15:28–16:40 (sunset 16:19).
Evening golden hour, flat horizon, local time:
| Evening | 20 Mar | 21 Jun | 23 Sep | 21 Dec |
|---|---|---|---|---|
| Singapore | 18:48–19:28 | 18:43–19:26 | 18:33–19:13 | 18:34–19:18 |
| Los Angeles | 18:32–19:20 | 19:31–20:25 | 18:15–19:04 | 16:09–17:05 |
| Ljubljana | 17:35–18:32 | 20:10–21:20 | 18:19–19:17 | 15:28–16:40 |
| London | 17:29–18:34 | 20:27–21:50 | 18:13–19:18 | 14:52–16:18 |
| Oslo | 17:36–18:56 | 21:24–23:35 | 18:20–19:40 | 13:06–15:49 |
| Reykjavík | 18:40–20:12 | from 22:07, through the night | 18:23–19:55 | 10:30–16:22 (one band all day) |
In Reykjavík in June the sun never sinks to −4°, so the evening golden hour runs through the night into the next morning's. In December it never climbs above 6°, so the whole short day is one golden band.
How long is golden hour?
About 40 min near the equator and 57 min at 46° N at the equinox; at high latitudes it stretches to hours in summer. The farther from the equator, the shallower the sun's path and the longer it spends between −4° and +6°.
Length of the morning golden hour:
| Morning length | 20 Mar | 21 Jun | 23 Sep | 21 Dec |
|---|---|---|---|---|
| Singapore | 40 min | 43 min | 40 min | 44 min |
| Los Angeles | 49 min | 55 min | 49 min | 56 min |
| Ljubljana | 57 min | 1 h 9 min | 58 min | 1 h 12 min |
| London | 1 h 4 min | 1 h 22 min | 1 h 5 min | 1 h 27 min |
| Oslo | 1 h 20 min | 2 h 11 min | 1 h 21 min | 2 h 43 min |
| Reykjavík | 1 h 32 min | through the night | 1 h 32 min | 5 h 52 min (all day) |
When is blue hour?
Blue hour is when the sun is 6° to 4° below the horizon, just before the morning golden hour and just after the evening one. In Ljubljana on 21 December it is 07:06–07:19 and 16:40–16:54.
| Blue hour | 20 Mar | 21 Jun | 23 Sep | 21 Dec |
|---|---|---|---|---|
| Singapore | 06:48–06:56 and 19:28–19:36 | 06:38–06:47 and 19:26–19:35 | 06:33–06:41 and 19:13–19:21 | 06:39–06:47 and 19:18–19:26 |
| Los Angeles | 06:32–06:41 and 19:20–19:30 | 05:13–05:24 and 20:25–20:37 | 06:17–06:26 and 19:04–19:13 | 06:27–06:37 and 17:05–17:15 |
| Ljubljana | 05:36–05:48 and 18:32–18:44 | 04:32–04:48 and 21:20–21:35 | 06:20–06:31 and 19:17–19:28 | 07:06–07:19 and 16:40–16:54 |
| London | 05:31–05:44 and 18:34–18:47 | 03:55–04:15 and 21:50–22:09 | 06:14–06:27 and 19:18–19:31 | 07:23–07:38 and 16:18–16:34 |
| Oslo | 05:38–05:54 and 18:56–19:12 | 00:00–00:28 and 02:10–03:02 and 23:35–00:00 | 06:21–06:37 and 19:40–19:56 | 08:20–08:41 and 15:49–16:09 |
| Reykjavík | 06:42–07:00 and 20:12–20:31 | none | 06:25–06:44 and 19:55–20:14 | 10:03–10:30 and 16:22–16:49 |
Why do golden hour calculators get the mountains wrong?
Because they assume a flat horizon. In a valley the sun is hidden until it clears the ridge, often above 6°, so the calculated golden hour happens in the sky but never reaches the ground.
Bovec is 80 km from Ljubljana and has nearly the same golden hour by the sky (07:24–08:37 and 15:31–16:43 on 21 December), but its first direct sun that day arrives at 08:52 with the sun already 8° high. Golden hour in the mountains explains the 6° rule; why sunrise time isn’t when the sun reaches you explains the skyline.
Frequently asked questions
Is golden hour exactly one hour?
No. Its length depends on latitude and season: about 40 min in Singapore and 2 h 43 min in Oslo on 21 December (morning), for the −4° to +6° definition.
Does golden hour depend on the weather?
The timing does not; the colour does. Clear air and some high cloud toward the sun give the strongest colour; thick low cloud on the horizon blocks it.
What is the difference between golden hour and magic hour?
Nothing in practice: "magic hour" is the film industry's name for the same low-sun period around sunrise and sunset.
Sources
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