Fall (autumn) starts in the month of September, but the exact date depends on the definition used:

• Astronomical fall begins with the autumnal equinox, which usually falls on September 22 or 23 in the Northern Hemisphere. For example, in 2025, the autumnal equinox-and thus the start of fall-will be on Monday, September 22

• Meteorological fall starts on September 1 and lasts through November 30. This method divides the year into four fixed three-month seasons for consistency in weather statistics and forecasting

In summary, fall generally starts in September, either on the 1st (meteorological) or around the 22nd/23rd (astronomical)