When Is Solar Noon in Yokohama?
In Yokohama, the sun reaches its highest point well before the clock strikes noon. A vertical stick casts its shortest shadow roughly 10 to 30 minutes early, depending on the season. For photographers, that moment delivers the harshest, most direct overhead light. For navigators, it is the reference for finding latitude.
Most people expect this to happen at 12:00. In Yokohama, it does not.
Why Yokohama Solar Noon Never Matches Clock Noon
Japan Standard Time is fixed to the 135°E meridian, the line that runs through Akashi City in Hyōgo Prefecture. Yokohama sits at 139.650°E, roughly 4.65 degrees east of that reference line.
Every degree of longitude equals four minutes of time. Yokohama's solar noon naturally occurs earlier than clock noon by about 18 to 19 minutes, purely from longitude.
But that is not the full story.
Why Yokohama Solar Noon Shifts Through the Year
Two things pull solar noon away from a fixed clock time in Yokohama.
Longitude offset
Yokohama is east of the JST meridian. That pushes solar noon earlier by about 18 minutes.
The Equation of Time
Earth's orbit is an ellipse, not a circle, and its axis is tilted. These two irregularities mean the sun's apparent motion across the sky speeds up and slows down over the year. That changes when solar noon occurs by up to 16 extra minutes.
Combine both factors, and you get the full seasonal range.
Yokohama Solar Noon in December: Around 11:30 JST
In December, two things happen. Earth is near perihelion, its closest point to the sun, which speeds up the apparent solar motion. The tilt also aligns in a way that pushes solar noon earlier.
On the December solstice, 21 December 2026, sunrise is at 06:46 and sunset at 16:32. That is a short day of 9 hours and 46 minutes of daylight. Solar noon falls at about 11:30 JST.
That is the earliest solar noon of the year. A midday photo shoot in December peaks nearly half an hour before a watch says 12:00.
Yokohama Solar Noon in June: Around 11:50 JST
June is the opposite. Earth is near aphelion, its farthest point from the sun, slowing the apparent solar motion. The tilt now delays solar noon.
On the June solstice, 21 June 2026, sunrise is at 04:26 and sunset at 18:59. That gives 14 hours and 33 minutes of daylight. Solar noon lands at about 11:50 JST.
That is the latest solar noon of the year. Still roughly 10 minutes before clock noon, but much closer to 12:00 than in December.
How the Equation of Time Shapes Yokohama Solar Noon
The equation of time is the difference between apparent solar time, what a sundial reads, and mean solar time, what a clock says. It is a curve that goes through four peaks and valleys each year, swinging about 14 minutes early and about 16 minutes late.
For Yokohama, the equation of time adds to the roughly 18 minutes from longitude. The combined offset ranges from about 30 minutes early in December to about 10 minutes early in June. The exact daily value changes slowly, by about a minute every three or four days at the steepest parts.
How Yokohama's Longitude Affects Solar Noon
Yokohama's coordinates are 35.433°N, 139.650°E. The JST reference meridian is 135°E. The difference is 4.65 degrees.
4.65 degrees times four minutes per degree equals 18.6 minutes.
If Japan used local solar time instead of JST, Yokohama's clocks would be about 18 minutes ahead of Akashi's. Because JST is a single zone, that 18 minutes shows up in the solar noon offset instead.
Using Yokohama Solar Noon for Photography, Navigation and Sundials
Photography
The golden hour around sunrise and sunset gives soft, warm light. Solar noon gives the opposite: harsh overhead shadows. Shooting in Minato Mirai or near the port means knowing the exact solar noon helps avoid the worst light. In December, that is 11:30, not 12:00. In June, it is 11:50.
Navigation
A noon sight, measuring the sun's altitude at solar noon, gives latitude. For a correct reading, the exact JST of solar noon is essential. Using 12:00 JST in December would introduce an error of about 7.5 nautical miles.
Sundials
A properly aligned sundial in Yokohama will read about 18 minutes fast compared to JST in June, and about 30 minutes fast in December. The equation of time correction is needed to convert.
Outdoor scheduling
A midday event in an open space, a park picnic, a school sports day, a construction job, hits peak UV and vanishing shadows at solar noon. Plan around it.
Quick Reference: Yokohama Solar Noon
| Season | Approximate Solar Noon (JST) | Notes |
|---|---|---|
| December solstice (21 Dec) | 11:30 | Earliest of the year |
| March equinox (20 Mar) | 11:43 | Mid-range |
| June solstice (21 Jun) | 11:50 | Latest of the year |
| September equinox (22 Sep) | 11:42 | Mid-range |
The daily shift is gradual. Between January and June, solar noon moves later by about 20 minutes. Between July and December, it moves earlier by about 20 minutes. The curve is not linear. The fastest changes happen around the equinoxes, the slowest around the solstices.
Common Yokohama Solar Noon Mistakes to Avoid
Don't assume solar noon equals 12:00. Don't use a single solar noon value year-round. Don't confuse solar noon with the time of maximum heat, which lags by an hour or two. And don't look for solar noon at the same clock time from month to month. It moves.
For more context on how Yokohama's daylight hours change across the year, the Yokohama Daylight Hours: Seasonal Guide to Sunlight covers sunrise and sunset across all four seasons. The Yokohama Time Zone: JST, UTC+9 & Asia/Tokyo Explained explains why JST is UTC+9 and how the time zone was set.