Solar Noon Calculator: When Is the Sun Highest?

Solar noon (local apparent noon) is the moment when the Sun reaches its highest point in the sky for the day. This is when sundials show exactly 12:00.

Simple approximation (no equation of time):

Solar noon (UTC) ≈ 12:00 − longitude / 15

The factor 15 comes from Earth rotating 360° in 24 hours → 15° per hour.

The Equation of Time (EoT): Due to Earth’s elliptical orbit and axial tilt, solar noon can differ from clock noon by up to ±16 minutes. This difference is called the Equation of Time.

Approximate EoT formula: EoT ≈ 9.87 sin(2B) - 7.53 cos(B) - 1.5 sin(B) (minutes)

Where B = 360/365 × (day_of_year - 81) degrees.

The analemma: If you photographed the Sun at the same clock time each day for a year, it would trace a figure-8 pattern in the sky called the analemma. The horizontal position shows the Equation of Time; the vertical position shows the Sun’s declination.

Longitude convention:

• Positive (+) = East of Greenwich (Europe, Asia, Africa, Australia)
• Negative (−) = West of Greenwich (Americas)

Practical note: Legal (civil) noon is determined by time zones, which are fixed 15° bands (in theory). Real time zones follow country and state borders, so they can differ significantly from true solar noon. Western China runs on UTC+8 despite sitting at longitudes that would suggest UTC+5, and far western Spain runs on UTC+1 when its longitude argues for UTC+0, so solar noon in both places can land 2 to 3 hours away from clock noon.

Daylight Saving Time. This is the correction people most often forget, and it is worth a full hour. Enter the offset your clocks are actually on right now, not the region’s winter standard. New York is UTC−5 in winter but UTC−4 from March to November, so entering −5 in July will put every answer an hour early. The Sun does not observe daylight saving; only the clock you compare it against does, which is why solar noon drifts to around 13:00 for half the year in any country that shifts.