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When is the autumnal equinox?

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The autumnal equinox occurs on September 22 or 23 in the Northern Hemisphere or March 20 or 21 in the Southern Hemisphere. In 2026 the Northern Hemisphere autumnal equinox happens on September 23 at 00:05 Universal Time (UT), and the Southern Hemisphere autumnal equinox occurs on March 20 at 14:46 UT.