When is Fall?

What is Fall?

Fall is another name for the autumn season, one of Earth's four temperate seasons. It occurs between summer and winter when the temperatures gradually decrease, and the leaves change color and fall from the trees. The Fall runs from September to November in the Northern Hemisphere and from March to May in the Southern Hemisphere. Fall is more common in American English, while Autumn is more formal and widely used in British English.

What is the Autumnal (Fall) Equinox?

The autumnal equinox, also known as the fall equinox, is the moment when day and night are approximately equal in length. It marks the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere. It typically occurs on September 22 or 23 in the Northern Hemisphere and March 20 or 21 in the Southern Hemisphere.

During the autumnal equinox, the sun crosses the celestial equator, an imaginary line that divides the Earth into the Northern and Southern Hemispheres. This event marks a significant shift in the Earth's tilt, resulting in:

1. Shorter days and longer nights in the Northern Hemisphere, as the North Pole tilts away from the sun.
2. Longer days and shorter nights in the Southern Hemisphere, as the South Pole begins to tilt towards the sun.

The autumnal equinox dates back to ancient times, when humans first observed the changing seasons and the movement of the sun, moon, and stars. The word "equinox" comes from the Latin words "aequus," meaning "equal," and "nox," meaning "night."

When does Fall Start and End?

How many days is Fall time?

The duration of fall varies depending on the hemisphere and the specific location. Fall in the Northern Hemisphere lasts approximately 89.8 days, while in the Southern Hemisphere it lasts close to 92.8 days.

What is Meteorological Fall?

Meteorological fall refers to the period of the year defined by meteorologists and climatologists as the three months of September, October, and November in the Northern Hemisphere and March, April, and May in the Southern Hemisphere.

This definition is based on the average temperature and precipitation patterns in each hemisphere rather than the astronomical definition of fall, which relies on the Earth's rotation around the Sun.

Meteorological fall is a practical concept. It provides a more consistent and predictable pattern of weather conditions than the astronomical definition of fall in weather forecasting and climate studies. This predictability helps you plan and prepare for the changing seasons, making you feel more informed and ready for what's to come.

According to the meteorological calendar, autumn begins on September 1 and ends on November 30.

Related: What is the first day of each season?