As summer winds down, many wonder when fall officially begins. Meteorologists say September 1 marks meteorological autumn’s start. But astronomers point to the equinox, a key solar event.
When Does Fall Start in the Northern Hemisphere?
This year, the autumn equinox falls on Monday, September 22. It happens at 2:19 p.m. Eastern Daylight Time, or 18:19 UTC. At this moment, day and night are nearly equal worldwide. The equinox signals the start of fall above the equator. Below the equator, it marks the start of spring.
What Happens During the Equinox?
At equinox, the sun is passing over Earth's equator, moving south. Earth's axis is not tilted toward or away from the sun. As a result, nearly equal daylight and darkness occur globally. However, the equinox does not bring exactly equal light. Atmospheric refraction makes the sun appear above the horizon. That effect extends daylight by several minutes. At the equator, the day lasts about 12 hours and 6 minutes. At 30 degrees latitude, it lasts 12 hours and 8 minutes. At 60 degrees latitude, daylight stretches to 12 hours and 16 minutes.
How Can People Witness the Equinox?
On September 22, the sun sets due west. This happens only during the September and March equinoxes. Observers can see this phenomenon at sunset if skies are clear. Ancient cultures paid close attention to equinox light changes. In Mexico, Chichén Itzá shows seven snake-like shadows at sunset. These shadows appear on the Pyramid of Kukulcán’s steps. In Cambodia, Angkor Wat’s equinox sunrise aligns with its causeway.
What Follows After the Equinox?
Autumn will continue until the winter solstice on December 21. The solstice is the shortest daylight time of the year. Daylight hours will gradually lengthen after December 21. The next equinox is on March 20, 2026, ushering in spring.
The autumn equinox this year provides an opportunity to experience nature's equilibrium. It reminds us how Earth's rotation creates the seasons.
Discover the latest Business News, Sensex, and Nifty updates. Obtain Personal Finance insights, tax queries, and expert opinions on Moneycontrol or download the Moneycontrol App to stay updated!
