September 22: Hello, Fall And Spring! At around 19:21 UTC on Wednesday, September 22, the Sun will be directly over the Earth's equator. This moment marks the first day of astronomical fall or autumn in the Northern Hemisphere and the start of astronomical spring in the Southern Hemisphere. When does the equinox happen in your city? Are you a developer who needs accurate and well-maintained time, date, or astronomy databases? Look no further than our API offerings. We have just released a sparkly new API website that is even easier to use. Check it out! The Full Moon on September 20 (23:54 UTC) is Northern Hemisphere's Harvest Moon (the Full Moon closest to the autumnal equinox). Southern Hemisphere dwellers will have to wait until the March equinox to spot their Harvest Moon. Why is it called the Harvest Moon? | 