Overview
- Meteorological autumn runs on a fixed schedule from September 1 to November 30 for statistical consistency.
- The astronomical start is the equinox, when the Sun’s apparent path crosses the celestial equator from north to south.
- Daylight is not exactly 12 hours at the equinox because atmospheric refraction and the Sun’s disk extend sunrise and sunset.
- In Germany around 50°N, the Sun is visible for roughly 12 hours and 11 minutes on September 22, with practical equal light and dark (Equilux) arriving a few days later.
- The equinox time varies annually, with upcoming starts listed as September 23, 2026 at 02:04, September 23, 2027 at 08:00, and September 22, 2028 at 13:45.