Noon Sun Height: How Latitude and Date Set the Sun's Highest Point

On a summer day the noon Sun can feel as if it is standing right over your head. In winter it hangs low and throws long shadows, even at the same clock time. Both are the same Sun at its highest point of the day. What changes is how high that highest point is, and two numbers decide it: your latitude and the date.

This guide gives the rule in plain steps, checks it against official data from the U.S. Naval Observatory, and shows where the Sun can stand directly overhead. It ends with a task in the Orbit Dial: finding the latitude where the noon Sun stands 60 degrees high on the March equinox.

What noon Sun height means

Astronomers call the Sun's height its altitude. The Naval Observatory defines altitude as the angular distance of a body above or below the horizon. A Sun on the horizon has an altitude of 0 degrees. A Sun straight overhead has an altitude of 90 degrees.

Solar noon is the moment the Sun reaches its highest point that day. It is not the same as 12:00 on a clock. The Naval Observatory notes that our clocks do not keep Sun time, and that the two can differ by as much as 16 minutes at some times of year. At longitude 0°, the Naval Observatory lists the Sun's highest point at 12:07 Universal Time on March 20, 2026, at 12:02 on June 21 and at 11:58 on December 21.

The equinox rule

At the equinox, the noon Sun's altitude is 90 degrees minus your latitude. NCAR's High Altitude Observatory states it that way, and NASA Goddard's navigation lesson gives the same rule: at the equinox, the noon Sun's altitude is 90 minus the degree of latitude.

Try it with a few places. At the equator, 90 minus 0 is 90, so the Sun is straight overhead at noon on the two equinoxes, as the National Weather Service says. At 40° N, the noon Sun stands 50 degrees high. At 60° N, it stands 30 degrees high.

The Naval Observatory's data service agrees. For 30° N on March 20, 2026, it gives a computed Sun altitude of 59.96 degrees at the Sun's highest point. That is a hair under 60 because the equinox itself falls at 14:46 Universal Time that day, so at 12:07 the Sun is still 0.04 degrees south of the equator.

The solstice rule

The tilt moves the Sun's noon height up or down from the equinox value. NCAR's High Altitude Observatory says the difference between the equinox and the solstices is plus or minus 23.5 degrees. NASA Goddard writes the two solstice cases out:

• June solstice: the noon altitude is (90 + 23.5) minus the latitude.
• December solstice: the noon altitude is (90 − 23.5) minus the latitude.

NCAR gives an example for 36 degrees of latitude: 77.5 degrees at the summer solstice, 54 at the equinoxes and 30.5 at the winter solstice.

The Naval Observatory's computed values show the same pattern. They use the Sun's exact position on each date, which is 23.44 degrees from the equator at the June solstice. That is a little under the rounded 23.5, so the values differ from the simple rule by a few hundredths of a degree.

Read the table down any column and the Sun drops one degree for each degree of latitude. Read it across any row and the three dates are about 23.4 degrees apart, which is the tilt of Earth's axis. See the guide on the axial tilt for where that number comes from.

Where the Sun is directly overhead

The noon Sun reaches 90 degrees only between the two tropics. The tilt shows why. At the June solstice the Sun is over the Tropic of Cancer at 23.5° N, and at the December solstice it is over the Tropic of Capricorn at 23.5° S, according to the National Weather Service. NOAA adds that outside the tropic zones, north or south, the Sun is never directly overhead.

Between the tropics, the Sun is overhead twice a year. NASA calls those days zero-shadow days, because objects cast only a minimal shadow at solar noon. On the equator they fall on the two equinoxes. On the Tropic of Cancer, the zero-shadow day comes on the June solstice.

The rule even tells you when the Sun is not in the south. NASA Goddard notes that if the formula gives more than 90 degrees, the noon Sun passes north of you. That happens in June at the equator, where the table above shows the Sun 66.6 degrees up in the northern sky.

Common mistakes

• Using 90 minus latitude on any date. That shortcut is only for the equinox. At a solstice you must add or subtract the tilt.
• Expecting the Sun overhead in summer everywhere. North of 23.5° N, the Sun is never directly overhead, even on the longest day.
• Treating clock noon as solar noon. The Sun's highest point can come several minutes before or after 12:00 by the clock.
• Mixing up altitude and direction. Altitude is height above the horizon. The direction along the horizon is a separate number.
• Thinking 23.5 is exact. The Naval Observatory uses 23.4 and its data show 23.44 degrees on June 21, 2026. The rounding changes answers by hundredths of a degree.
• Looking at the Sun to measure it. NASA's eclipse viewing safety page says it is not safe to look directly at the Sun without specialized eye protection for solar viewing. Its only exception is the brief totality of a total solar eclipse. Work from tables, not from squinting.

Try it in the instrument

Open the Orbit Dial and set the sky to the latitude in the Northern Hemisphere where the noon Sun stands 60 degrees above the horizon on the March equinox. The dial takes a date in 2026 and a latitude, then shows the Sun's height at noon and the length of the day.

Set the date to the March equinox, March 20, 2026. Then move the latitude until the noon height reads 60 degrees. The rule gives the answer: 90 minus 60 is 30, so the target is 30° N.

The official check is the Naval Observatory's 59.96 degrees at 30° N on that date. If you pick 40° N you get about 50 degrees, and at 50° N about 40, so each step of 10 degrees of latitude moves the Sun by 10 degrees. The dial is a simplified model, so allow for a small difference from an official table. The relation is the point: at the equinox, height and latitude add up to 90.

For another look at the same date, see the guide on the spring equinox.

Questions people ask

How high is the noon Sun at the equinox where I live?

It is 90 degrees minus your latitude. At 40° N that is 50 degrees, and the Naval Observatory's data give 49.96 degrees on March 20, 2026.

Why is the noon Sun lower in winter?

On the December solstice the Sun's noon height drops by the tilt, 23.4 degrees, from its equinox value. At 40° N the Naval Observatory's data give 26.6 degrees on December 21, 2026.

Where is the Sun directly overhead at noon?

Between the Tropic of Cancer at 23.5° N and the Tropic of Capricorn at 23.5° S, twice a year. Nowhere outside those lines, according to NOAA.

Is solar noon the same as noon on my watch?

No. Clocks keep uniform time, while the Sun's apparent motion varies, so the two can differ by up to about 16 minutes, according to the Naval Observatory.

What does altitude mean here?

The angle of the Sun above the horizon, from 0 degrees at the horizon to 90 degrees straight overhead.

Sources

• Horizon Calendars, NCAR/UCAR High Altitude Observatory. https://www2.hao.ucar.edu/education/prehistoric-southwest/horizon-calendars. Opened November 10, 2026.
• Navigation--lesson plan #8, NASA Goddard Space Flight Center (From Stargazers to Starships). https://pwg.gsfc.nasa.gov/stargaze/ILnavigat.htm. Opened November 10, 2026.
• Application Programming Interface Documentation, U.S. Naval Observatory. https://aa.usno.navy.mil/data/api. Opened November 10, 2026.
• Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion, U.S. Naval Observatory. https://aa.usno.navy.mil/data/Earth_Seasons. Opened November 10, 2026.
• Glossary, U.S. Naval Observatory. https://aa.usno.navy.mil/faq/asa_glossary. Opened November 10, 2026.
• Sunrise and Sunset Times Near the Solstices, U.S. Naval Observatory. https://aa.usno.navy.mil/faq/rs_solstices. Opened November 10, 2026.
• The Seasons and the Earth's Orbit, U.S. Naval Observatory. https://aa.usno.navy.mil/faq/seasons_orbit. Opened November 10, 2026.
• The Astronomical Seasons Page, National Weather Service, Tucson. https://www.weather.gov/twc/Astronomical_Seasons. Opened November 10, 2026.
• The Seasons (Equinoxes and Solstices) Page, National Weather Service, Quad Cities. https://www.weather.gov/dvn/Climate_Astronomical_Seasons. Opened November 10, 2026.
• What Is a Solstice?, NOAA NESDIS. https://www.nesdis.noaa.gov/about/k-12-education/optical-phenomena/what-solstice. Opened November 10, 2026.
• Tropical Solstice Shadows, NASA Science (Night Sky Network). https://science.nasa.gov/solar-system/skywatching/night-sky-network/tropical-solstice-shadows/. Opened November 10, 2026.
• Eclipse Viewing Safety, NASA Science. https://science.nasa.gov/eclipses/safety/. Opened November 10, 2026.

We opened each source ourselves on the date shown. The drawings are our own and were checked against the numbers in these sources.

Read next

• Spring EquinoxAt the March equinox the Sun stands over the equator and day and night come out nearly equal, though not exactly.
• Earth’s Axial TiltEarth's axis leans about 23.4 degrees from the perpendicular to its orbit.