September Equinox in Altoona, Pennsylvania, USA is on
Thursday, September 22, 2016 at 10:21 AM EDT
Not Entirely Equal Day & Night
On the two equinoxes every year the Sun shines directly on the Equator and the length of day and night is nearly equal – but not exactly.
The September equinox marks the moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s equator – from north to south and vice versa in March.