In the Northern Hemisphere, the Harvest Moon is the full moon closest to the autumn equinox. Depending on the year, the full Harvest Moon can occur anywhere from two weeks before the autumn equinox to two weeks after. Thus, the Harvest Moon is either the last full moon of the summer season or the first full moon in autumn.— EarthSky.
In 2021, the Northern Hemisphere autumn equinox comes on September 22. The full moon falls less than two days earlier, on September 20. Thus, for the Northern Hemisphere, this upcoming full moon is the Harvest Moon and the last full moon of summer.
As it happened, clouds and rain obscured my view of the full harvest moon. But not all was lost.
Six days prior, on 14 September, I looked up at the (only slightly clouded) night sky over Atlanta, Georgia, USA, and saw the moon, beautiful even if it was only 52% illuminated and waxing gibbous, announcing the impending end to summer.
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