Questions
Short answers to the questions people ask most about the Sun’s year, each with a way to go deeper.
Why isn’t the earliest sunset on the shortest day?
Because solar noon itself drifts later through December. Around the December Solstice the solar day runs about 30 seconds longer than 24 hours, so noon, sunrise and sunset all slide later each day. The length of daylight barely changes near the solstice, so that drift wins: sunsets start getting later in early December, while sunrises keep getting later until early January. At 40° north, the earliest sunset comes around December 7 and the latest sunrise around January 5.
Is Earth closest to the Sun in winter?
For the Northern Hemisphere, yes. Earth is closest to the Sun at perihelion, January 3 in 2026, at 147.1 million km, and farthest at aphelion, July 6, at 152.1 million km. The difference brings about 7% more sunlight in January, but the seasons come from the tilt of Earth’s axis, not its distance.
Why doesn’t a sundial match my clock?
A clock keeps every day exactly 24 hours long; the Sun does not. Because Earth’s orbit is an ellipse and its axis is tilted, the sundial runs up to 16 minutes ahead of the clock in early November and 14 minutes behind it in mid-February. That gap is the equation of time. Your position within your time zone and daylight saving add their own offsets. Neither is wrong; they keep different time.
Why are the seasons different lengths?
Because Earth moves faster when it is closer to the Sun. It passes perihelion in early January, so it hurries through the northern winter (about 89.0 days in 2026) and lingers through the northern summer (about 93.7 days).
Why does the equinox date change from year to year?
A calendar year is 365 days, but the year of the seasons is about 365 days and 6 hours, so each equinox lands about six hours later than the year before, until a leap day pulls it back. Over a century the date creeps earlier, and a skipped leap day, as in 1900 and 2100, resets it. Between 1900 and 2100, the March Equinox falls as early as March 19 (2096) and as late as March 21 (1903), in UTC.
Are day and night equal on the equinox?
Not quite. Sunrise and sunset are counted from the Sun’s upper edge, not its center, and the atmosphere bends its light over the horizon, so at most latitudes the equinox day runs several minutes longer than 12 hours. In the Northern Hemisphere, day and night are equal a few days before the March Equinox and a few days after the September Equinox; in the Southern, the other way around.
When is the Sun highest in the sky?
At solar noon, which is rarely 12:00 on the clock. It shifts by the equation of time (up to about a quarter of an hour either way), by where you are within your time zone (four minutes for each degree of longitude from its center), and by an hour during daylight saving.
What is the analemma?
The shape the Sun traces if you mark its place in the sky at the same clock time every day for a year: a tall, lopsided figure eight. Its height comes from the tilt of Earth’s axis, its width from the equation of time.
How long is a year, exactly?
It depends on what you measure from. The year of the seasons, the tropical year, averages 365 days, 5 hours, 48 minutes and 45 seconds around the whole orbit; from one particular equinox or solstice to the next it runs up to about a minute different. Measured against the stars it is about 20 minutes longer, and from one perihelion to the next about 25 minutes longer.
What are cross-quarter days?
The four moments halfway between a solstice and an equinox, in early February, May, August and November. They sit behind the Gaelic festivals of Imbolc, Beltane, Lughnasadh and Samhain, and the same instants open the seasons in the East Asian solar calendar.
What are Earlysun, Evensun and the other new names?
The turning points of the equation of time and of Earth’s distance from the Sun, which never had names: the days the sundial runs furthest ahead (Earlysun) or behind (Latesun), agrees with the clock (Evensun), and so on. Solmanac names them so they can be found and marked like the solstices.