Fall 2020

Fall 2020 starts on Tuesday, September 22, 2020 (in 2 days) and ends on Monday, December 21st 2020 (in 92 days).  Calendar for 2020

Please note: The dates given on this page are based on Coordinated Universal Time (UTC), which for practical purposes is equivalent to Greenwich Mean Time (GMT). While Fall starts and ends at the same moment in time all over the Northern Hemisphere, the date and local time differ from location to location depending on a location's time zone. For more details see the explanations below.

Fall, usually called autumn outside of North America, is one of the four seasons that make up the year. It is the intervening period between the warmest time of the year, summer, and the coldest time of the year, winter.

Astronomical fall vs. meteorological fall

There are various ways to define the start and end dates of fall. The two most commonly used ones are based on the astronomical calendar and the meteorological calendar. Astronomical and meteorological fall start and end on different dates.

Astronomical fall

In the astronomical calendar the start and end dates of fall are based on the changing position of Earth in relation to the sun and the resulting solar events of equinoxes and solstices. In the Northern Hemisphere summer ends and fall starts at the moment of the September equinox, which occurs every year between September 21 and 24. Fall ends and winter starts at the moment of the December solstice, which occurs every year between December 20 and December 23. In the Southern Hemisphere fall lasts from the March equinox (March 19 to 21) to the June solstice (June 20 to 22).

The start and end dates for fall given on this page are the dates of astronomical fall in the Northern Hemisphere and are based on Coordinated Universal Time (UTC), which for practical purposes is equivalent to Greenwich Mean Time (GMT - the time zone of the United Kingdom). While fall starts and ends at the same moment in time all over the Northern Hemisphere, the date and local time differ from place to place depending on the year and a location's time zone. For locations that are ahead of UTC (further east) it may fall on the day after, and for locations that are behind UTC (further west) it may fall on the day before. To find out the exact date and time of fall 2020 in your area use this seasons calculator.

Meteorological fall

Meteorologists, on the other hand, define seasons based on climatic conditions and the annual temperature cycle. It is important for them to be able to compare the same period of time in different years. The length of the astronomical seasons varies between 89 and 93 days, while the length of the meteorological seasons is less variable and is fixed at 90 days for winter in a non-leap year (91 days in a leap year), 92 days for spring and summer, and 91 days for fall. While the exact definition of a season's timing and length can differ in different areas based on local conditions, in most of the Northern Hemisphere meteorological fall is generally defined as the three months of September, October and November, with the season starting on September 1 and ending on November 30.

There is no "official rule" which definition of fall to use, and different countries adhere to different conventions. Most of North America and Europe use astronomical fall, while Australia and New Zealand use meteorological fall (however, as these countries are in the Southern Hemisphere, the seasons are opposed and fall there lasts from March to May). In other cultures, eg. in the traditional Chinese calendar and in Celtic traditions, the September equinox is considered to be roughly the middle of fall.

Further reading:
• Autumn (Fall) on Wikipedia
• Seasons in general on Wikipedia

Comparison table: meteorological spring vs. astronomical spring

Dates shown apply to the Northern Hemisphere and are based on UTC (GMT)

Season	Start		End
	Meteorological	Astronomical	Meteorological	Astronomical
Spring	March 1	March 19 to 21 Spring equinox (vernal equinox, March equinox)	May 31	June 20 to 22 Summer solstice (June solstice)
Summer	June 1	June 20 to 22 Summer solstice (June solstice)	August 31	September 21 to 24 Autumn equinox (Fall equinox, September equinox)
Autumn (Fall)	September 1	September 21 to 24 Autumn equinox (Fall equinox, September equinox)	November 30	December 20 to 23 Winter solstice (December solstice)
Winter	December 1	December 20 to 23 Winter solstice (December solstice)	February 28 (29)	March 19 to 21 Spring equinox (vernal equinox, March equinox)

Fall 2021 starts on Wednesday, September 22, 2021 (in 367 days) and ends on Tuesday, December 21st 2021 (in 457 days).  Calendar for 2021