The sun's position in the sky changes continuously throughout the day and year. Understanding solar altitude and azimuth is essential for applications ranging from solar energy to photography to architecture.
Solar Altitude (Elevation)
Altitude is the angle of the sun above the horizon, measured in degrees. At sunrise/sunset, altitude is 0°. When the sun is directly overhead (only possible between the tropics), altitude is 90°. In mid-latitudes, the sun never reaches 90° altitude. Higher altitudes mean shorter shadows and more direct sunlight.
Solar Azimuth
Azimuth is the compass direction of the sun, measured in degrees from true north (0°). East is 90°, south is 180°, and west is 270°. The sun rises in the east (roughly 90°) and sets in the west (roughly 270°), but exact values vary by season and latitude. At solar noon, azimuth is exactly 180° (due south in Northern Hemisphere).
Seasonal Variations
The sun's path changes dramatically with seasons. In summer, the sun rises north of east and sets north of west, reaching higher altitudes. In winter, it rises south of east and sets south of west, with lower maximum altitudes. The difference is more extreme at higher latitudes.
Solar Noon
Solar noon is when the sun reaches its highest point (maximum altitude) for the day. This doesn't always match 12:00 clock time due to time zones and the equation of time. At solar noon, shadows point directly north (in Northern Hemisphere) or south (in Southern Hemisphere).