Azimuth and elevation: how to read the sun’s position
The two angles that describe where the sun is, how to measure them with simple tools, and what they tell you about shade, light and solar energy.
Any point in the sky can be described with two angles, just like a place on a map can be described with latitude and longitude. For the sun, those two angles are azimuth and elevation.
Azimuth: the direction
Azimuth tells you which direction to look. It is measured in degrees clockwise from true north:
| Azimuth | Direction |
|---|---|
| 0° | North |
| 45° | North-east |
| 90° | East |
| 135° | South-east |
| 180° | South |
| 225° | South-west |
| 270° | West |
| 315° | North-west |
At mid-northern latitudes the sun rises in the east-north-east in summer (about 50° to 60°) and in the south-east in winter (about 120° to 130°). At solar noon it is due south (180°), everywhere north of the tropics. In the Southern Hemisphere outside the tropics it is due north (0°) at noon.
Elevation: the height
Elevation (astronomers often say altitude) is the angle between the horizon and the sun. The horizon is 0°, the point straight overhead (the zenith) is 90°. When the sun is below the horizon, the elevation is negative, which is how twilight is defined: civil twilight ends at −6°.
The highest elevation of the day is reached at solar noon. At 46° N (Ljubljana, Portland in Oregon) it is about 67° at the June solstice and only about 21° at the December solstice. A useful approximation: noon elevation = 90° − latitude + the sun’s declination, where the declination varies from +23.4° in June to −23.4° in December.
How to measure them yourself
- Elevation with your hand. Stretch your arm out fully. A fist covers roughly 10°, a thumb’s width about 2°. Four fists above the horizon means the sun is about 40° high. Never look at the sun directly; measure to the edge of the glare or use the shadow method.
- Elevation from a shadow. The shadow of a vertical stick of height h has length L. The elevation is arctan(h / L). If the shadow is as long as the stick, the elevation is 45°.
- Azimuth with a compass. Point a compass towards the sun (or along a shadow, and add 180°). Correct for magnetic declination, or switch your phone compass to true north.
- Azimuth from solar noon. At solar noon the shadow of a vertical stick points exactly north in the Northern Hemisphere (outside the tropics).
Why these two numbers matter
- Shade. Low elevation means long shadows. At 20° elevation a 10 m building casts a shadow 27 m long.
- Windows and balconies. A window only gets direct sun when the sun’s azimuth is within 90° of the direction the window faces, and when the sun is high enough to clear buildings opposite but low enough to get under a balcony above.
- Photos. The azimuth tells you where the light comes from; the elevation tells you how soft and warm it will be.
- Solar panels. Panels produce most when the sun shines on them head-on, which depends on both angles.
The sun position map shows azimuth and elevation for any place and time, with the day’s sun path drawn on the map, and the shadow calculator turns them into shadow lengths.
Frequently asked questions
What does sun azimuth mean?
Azimuth is the compass direction of the sun, measured clockwise from true north. 0° is north, 90° east, 180° south and 270° west. An azimuth of 135° means the sun is in the south-east.
What is sun elevation?
Elevation (also called altitude) is the sun's height above the horizon in degrees. 0° is on the horizon and 90° is straight overhead. Negative values mean the sun is below the horizon.
Is azimuth measured from magnetic north?
No. Astronomical azimuth uses true (geographic) north. A magnetic compass points to magnetic north, which can differ by several degrees, and by more than ten degrees in some regions. Most phone compasses can be set to show true north.
What is the sun's zenith angle?
The zenith angle is the angle between the sun and the point straight overhead. It is 90° minus the elevation. Solar engineers often use it instead of elevation.