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Solar altitude is the angle between the sun and the Earth’s horizon, measured in degrees. It indicates how high the sun appears in the sky and varies with the time of day, season, and latitude. Near the equator the sun can be almost directly overhead, while near the poles it never reaches high angles.
Solar altitude is the sun’s angle above the horizon, measured in degrees. It is 0° at sunrise and sunset, and can reach 90° at solar noon near the equator.
At the equator the sun can reach 90° during the equinoxes when it is directly overhead. The Earth’s 23.5° axial tilt means the sun is never directly overhead at the equator all year. In the Tropics of Cancer and Capricorn, 90° occurs on their respective summer solstices.
Because the Earth’s axis is tilted 23.5°, the sun’s apparent height rises during summer and falls during winter. This difference drives the temperature contrast between seasons. The hemispheres experience opposite seasons because of the tilt.
Solar altitude starts at 0° at sunrise, rises to a peak at solar noon, then falls back to 0° at sunset. Solar noon is not the same as clock noon. The peak value depends on latitude and season. For example, at 44° N during an equinox the noon altitude is 46°, while it climbs to 69.5° at the summer solstice and drops to 22.5° at the winter solstice.
The solar zenith angle is the complement of solar altitude (90° − altitude). If the altitude is 46°, the zenith angle is 44°. Azimuth measures the sun’s position relative to true north, increasing eastward. An east‑directed sun has an azimuth of 90°, north has 0°, south 180°, and west 270°. All these angles change throughout the day and year.
Understanding solar altitude is essential for fields ranging from architecture and solar energy to navigation and climate science.
