During an equinox, places around the globe experience nearly equal amounts of daytime and nighttime. The second occurrence this year happens on Sunday.

The Earth is prone to more geomagnetic storms during the spring and fall equinoxes than throughout the solstices.

On Sept. 22, the fall equinox formally heralds in autumn and marks the end of summer in the Northern Hemisphere.

According to Britannica, the fall equinox is one of two moments in the year when the sun is exactly above the equator. The celestial event happens annually around Sept. 22 or Sept. 23 in the Northern Hemisphere and on March 19 or March 20 in the Southern Hemisphere.

In Japan, Autumnal Equinox Day is a national holiday. In Japanese, it’s known as Shubun no Hi (秋分の日), according to Coto Japanese Academy. The roots of the celebration are thought to go back to Shintoism and Buddhism.

Sept. 22, marks the first day of the autumnal equinox in the Northern Hemisphere, according to the Farmer’s Almanac. It begins approximately at 8:43 a.m. ET. Meanwhile, meteorological fall begins on Sept. 1 and makes it easier to keep seasonal weather records, according to FOX Weather.

The equinox has no relationship to Houston’s weather, and the city’s climate afterwards isn’t guaranteed to bring cooler or warmer temperatures.

The autumnal equinox brings fall to the Northern Hemisphere today as the sun passes directly over the equator at noon. But are day and night actually equal length today?