Sun angle calculator

The sun's angle is two numbers: how high it is above the horizon, and which compass direction it's in. Search any address in Sundial, set a date and time, and the panel shows both, with the shadows they produce on the real buildings around you.

Free, no sign-up. Times are in the location's own time zone.

The two angles

Sun height is the angle between the horizon and the sun. Astronomers call it elevation or altitude, and they mean the same thing. It is 0° when the sun sits on a flat horizon and would be 90° if it were straight overhead. It decides how long shadows are and how strong the light feels. There's a full explanation on the solar elevation angle page.

Sun bearing is the compass direction of the sun, measured clockwise from north: 90° is due east, 180° due south, 270° due west. Its formal name is azimuth. It decides which way shadows point (always directly away from the sun) and which side of a building is lit.

A note if you use other tools. Some calculators, including the SunCalc library underneath Sundial, measure raw azimuth from south rather than north. Sundial converts it to an ordinary compass bearing before showing it, so 180° always means south.

How the angles change through the year in London

These come from the same formulas the map uses. Notice how far round the sunrise and sunset bearings swing between June and December.

In midsummer the sun rises in the north-east and sets in the north-west, so a north-facing garden can catch early and late sun. In midwinter it stays in the southern sky the whole time, rising in the south-east and setting in the south-west after under eight hours.

Clock times give a better feel for everyday use. Here is the same place at 9 am and 3 pm:

The March and September rows differ because of British Summer Time. In September the clocks are an hour ahead, so 9 am is earlier in the solar day and the sun is lower.

Further south the sun climbs higher. New York's noon sun reaches 72.7° in June and 25.8° in December. In the southern hemisphere everything flips: in Sydney the noon sun is in the north, and June is the low month at 32.7°.

Reading the angles in Sundial

1. Search an address, paste coordinates, or use your location.
2. Pick the date, then drag the time slider. It snaps to sunrise, solar noon and sunset.
3. Read Sun height (to a tenth of a degree) and Sun bearing (in degrees, with a compass point such as SW) in the panel.
4. Look at the map to see what those numbers mean on the ground: the sun's arc for the day is drawn over the buildings, beside the June and December arcs, and the shadows point away from the sun.

When the sun is below the horizon the height goes negative, which is a quick way to check whether it has set behind a flat horizon. Hills aren't modelled, so on a valley site the real sunrise will be later.

What the angles are useful for

Sun height tells you how far shadows reach. Divide an object's height by the tangent of the sun height to get its shadow length, or use the shadow calculator table. Bearing tells you which facade, window or bed faces the sun at a given hour, which matters for working out which way a house faces, angling a solar panel, or planning a photo.