When does fall start in the Northern Hemisphere? Whereas a meteorologist may inform you Sept. 1, the start of meteorological fall, an astronomer will notify you that seasons pivot on solstices and equinoxes — waymarkers of Earth’s journey around the sun that alter where, and for how long, sunshine strikes the world.

This year, the fall equinox takes place on Monday, Sept. 22 at 2:19 p.m. EDT (18:19 UTC), according to Time and Dateand it brings approximately equivalent day and equivalent night to the whole world. North of the equator, it’s been summer season, with more daytime than darkness, so September’s equinox marks the very first day of fall; south of the equator, it’s been winter season, with more darkness than daytime, so the equinox brings spring.

September’s equinox marks the specific time when the midday sun someplace on Earth crosses the equator, going southward. That’s since it’s a shift point, with the Northern Hemisphere tipped towards the sun before the equinox and the Southern Hemisphere after it. It’s when Earth’s axis is slanted neither towards nor far from the sun, leading to a practically equivalent quantity of daytime and darkness at all latitudes.Practically, however not rather– although the word “equinox” originates from the Latin words “aequus” (equivalent) and “nox” (night), it’s a little a misnomer. Since light rays from the sun bend, the sun can seem above the horizon when, in truth, it has actually currently set. That result is increased at greater latitudes due to the fact that the sun takes longer to increase and set. According to the National Weather Servicethat implies a day on the equinox lasts about 12 hours, 6 minutes at the equator; 12 hours, 8 minutes at 30 degrees from the equator; and 12 hours, 16 minutes at 60 degrees from the equator.

That’s tough to determine, and the equinox is typically difficult to see and value– however there’s a method. If you go outside at sundown on Sept. 22, you’ll observe that the sun dips listed below the horizon due west– something that happens just on the September and March equinoxes.

The altering instructions of shadows at the equinox was seen by lots of ancient cultures. At Chichén Itzá in Mexico, 7 triangular shadows looking like a snake appear to move down the actions of the Pyramid of Kukulcán on the equinox. At Angkor Wat in Cambodiathe equinox dawn predicts a shadow that lines up precisely with its causeway entryway.

It will stay fall in the Northern Hemisphere up until the winter season solstice– the quickest day of the year– on Dec. 21. After that, the days will grow progressively longer with the next equinox declaring the arrival of spring on March 20, 2026.