Fall Equinox 2026: What it means and when it happens

While many parts of the country are still experiencing hot weather, it’s comforting to know cooler temperatures could be on the way with the changing times. Today (Tuesday, September 22, 2026) marks the Fall Equinox, or the official beginning of astronomical autumn, in the Northern Hemisphere. This means sweaters, pumpkin-flavored snacks, and cozy fires can’t be too far away. (The opposite is true for those in the Southern Hemisphere.) Let’s take a look at the science behind this occasion so you can wow everyone in the office with your seasonal know-how. What are the two different ways to measure seasons? Most modern humans measure the seasons in one of two ways. Meteorologists have a cut-and-dried approach that focuses on annual temperatures, whole calendar months, and keeping clean records. Winter is December, January, February, followed by spring in March, April, May. Summer begins on June 1 and lasts until August 31. Fall begins on September 1 and ends on November 30. However, astronomers use the position of Earth in relation to the sun to determine seasons. When you measure this way, the exact dates change a bit each year. This is because the 365-day calendar does not perfect…