Solar Noon Calculator

Solar noon is the moment when the sun crosses your local meridian and reaches its highest point in the sky for that day. It's the midpoint between sunrise and sunset, and it's when shadows are at their shortest. Unlike clock noon (12:00 PM on your watch), solar noon varies throughout the year and depends on your longitude within your time zone.

Two main factors cause solar noon to drift from 12:00 PM clock time: longitude offset and the Equation of Time. Your longitude relative to your time zone's standard meridian can shift solar noon by up to ±30 minutes. The Equation of Time, caused by Earth's elliptical orbit and axial tilt, adds an additional variation of up to ±16 minutes throughout the year.

The Equation of Time (EoT) is the difference between apparent solar time (what a sundial shows) and mean solar time (what your clock shows). It varies from about -14 minutes to +16 minutes throughout the year due to Earth's elliptical orbit (which affects orbital speed) and the tilt of Earth's axis. When EoT is positive, the sundial is ahead of the clock, meaning solar noon arrives earlier than average.

The sun moves across the sky at 15° of longitude per hour. If you're west of your time zone's standard meridian, solar noon occurs later than clock noon (about 4 minutes later for every degree west). Conversely, if you're east of the standard meridian, solar noon comes earlier. This is why solar noon in Boston differs from solar noon in Detroit, even though both are in the Eastern Time Zone.

The sun's altitude at solar noon is its maximum angular height above the horizon for that day. It's calculated as 90° − |latitude − solar declination|. On the equinoxes, the altitude equals 90° minus your latitude. On the summer solstice, it's about 23.44° higher; on the winter solstice, about 23.44° lower. At the poles, the sun may not rise at all during winter (polar night) or stay up all day during summer (polar day/midnight sun).

Yes! At solar noon in the Northern Hemisphere, the sun is due south (azimuth ~180°). In the Southern Hemisphere, it's due north (azimuth ~0°). This makes solar noon an excellent time for determining cardinal directions using the sun's position. Navigators and surveyors have used this principle for centuries to find true north/south without a compass.

Day length is determined by the hour angle at sunrise/sunset, which depends on your latitude and the sun's declination. The formula is: cos(hour angle) = −tan(latitude) × tan(declination). Day length = 2 × hour angle / 15 hours. Near the poles, when this value exceeds ±1, you experience polar day (24-hour sunlight) or polar night (24-hour darkness).

Solar noon is the time when the sun is highest, while the zenith is the point directly overhead (90° altitude). The sun only reaches the zenith at solar noon if you're located between the Tropic of Cancer and the Tropic of Capricorn (within ±23.44° latitude) on the right day of the year. For most locations, the sun is never directly overhead, even at solar noon.

The Equation of Time has a characteristic double-humped curve throughout the year, but the exact timing of solar noon also depends on your longitude offset from the time zone meridian. The combination of these two effects means that the dates of earliest and latest solar noon shift slightly depending on how far east or west you are within your time zone.

This calculator uses standard astronomical formulas and is accurate to within about ±1 minute for most locations. However, it doesn't account for atmospheric refraction (which slightly raises the apparent sun position near the horizon) or local topography. For precise astronomical applications, consult specialized ephemeris data. Times are displayed in your browser's local timezone.