Moreover, autumn is not uniform across even a single month. The September of meteorological autumn can feel like lingering summer (the “second summer” or Indian summer). The November of that same system can bring snow flurries more akin to winter. The astronomical autumn’s December days—before the solstice—often hold some of the season’s most dramatic leaf falls and first hard frosts. So, what months are autumn? For the most widely accepted, practical, everyday answer: September, October, and November in the Northern Hemisphere; March, April, and May in the Southern Hemisphere. This is the meteorological definition used by weather services, schools, and most commercial calendars.
Few questions in seasonal reckoning are as deceptively simple as “What months are autumn?” At first glance, one might confidently answer “September, October, November” (in the Northern Hemisphere) or “March, April, May” (in the Southern Hemisphere). However, the true answer is layered, varying depending on whether you consult an astronomer, a meteorologist, a farmer, or a cultural tradition. Autumn, also known as fall, is not a fixed date on all calendars but a dynamic period defined by sunlight, temperature, and ecological change. This long-form exploration will dissect the different ways we assign months to autumn, the science behind each system, and the subtle beauty of a season that refuses to be pinned down to a single three-month block. The most common conflict in defining autumn’s months comes from two authoritative sources: astronomy and meteorology. Both are valid, but they serve different purposes. what months are autumn
In traditional East Asian culture, the year is divided into 24 solar terms. Autumn begins with Lìqiū (“Start of Autumn”), which usually falls around August 7 or 8 , and ends with Shuāngjiàng (“Hoar Frost Descends”) in late October, leading into Lìdōng (“Start of Winter”) around November 7. Thus, in the Chinese system, autumn effectively occupies August, September, and October —a full month earlier than the meteorological definition. Moreover, autumn is not uniform across even a single month