Weather Tidbits: Autumn Equinox & Daylight Loss

This Weather Tidbits answers the question why daylight loss is faster during the autumn equinox. The autumnal equinox begins in the northern hemisphere at 3:21 pm on Wednesday, September 22. This means that day and night are nearly equal; with the sun focused over the equator.

The reason we lose daylight quickly in the autumn equinox is due to the earth’s tilt, the speed of revolution around the sun and the Earth’s elliptical orbit. The best way to explain how daylight amount changes is with a pendulum that is swinging; which represents the year, with the ends being autumn & spring, and the middle being summer & winter. When the pendulum is near its end, its at its fastest rate of change which is right now for us with the equinox; but when its in the middle, it’s at its slowest rate of change which are the solstices. The days are getting shorter; but by late October it will begin to slow down from one day to another towards winter. Remember, this fast rate of daylight will happen again in 6 months in March but with more increased daylight each day.

Categories: Weather Tidbits