13.9 days old
99.2 percent lit
September 18, 2021By Dustin Jones
For those in the Northern Hemisphere, (click here) summer will come to an end next Wednesday. Slowly but surely since the middle of June, days have been getting shorter. With the arrival of the autumn equinox comes cooler weather and a change of color amongst the trees. And Monday, two days before the official start of fall, the harvest moon.
For three days, moonrise will come shortly after sunset, but the harvest moon will reach its peak illumination at 7:54 p.m. ET Monday. Historically this lunar event provided farmers a little extra light to harvest their crops. However, unlike the equinoxes, which take place at the same time each year, the harvest moon is the full moon closest to the autumnal equinox. Which means it can fall in September or October, according to The Old Farmer's Almanac.
But that's not all that changes with the last full moon of the summer. You may recall glancing up at the night sky and noticed the moon varies in size from time to time. That's because the its orbit around the Earth isn't a perfect circle, NASA explains....
