2. Why September Still Feels Like "Summer" (Climatic Perspective)
| Period | Designation | Characteristics | |--------|-------------|-----------------| | Sep 1 – Sep 20 | | High heat, summer recreation, late crops, ocean warmth, air conditioning | | Sep 21 – Sep 30 | Early Autumn | Cooling, leaf change, frost risk, migration, heating at night | september fall or summer
From a pure atmospheric science perspective, September is the first month of meteorological autumn in the Northern Hemisphere (September, October, November). This definition is based on the annual temperature cycle, not on calendar tradition. not on calendar tradition.