Today is the Autumnal Equinox, the first day of fall in the northern hemisphere. The new season officially arrives at 14:49 UTC (10:49 A.M. Eastern Daylight Time).

Seasons are the result of the tilt of the Earth’s axis, a 23.5° angle. Today, as autumn begins, the planet’s axis is tilted neither toward nor away from the sun. As a result, we receive approximately equal hours of day and night. In fact, the word “equinox” is Latin for “equal night”.

As a transitional season, autumn is a time when the heat of summer fades away and winter’s chill gradually returns. The largest drop in average temperature, however, usually lags the equinox by a few weeks.

Autumnal Equinox

Image Credit: Przemyslaw “Blueshade” Idzkiewicz