Are you ready for fall? The official arrival of fall is the autumnal equinox, which occurs in the Northern Hemisphere on Monday.

After a hot summer , the September equinox marks a welcome shift in the seasons for many folks. But what exactly is an equinox? It's all about Earth and its relationship with the sun. Here's how to understand, visualize and celebrate the autumnal equinox.

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When is the fall equinox?

This year, the autumnal equinox in the Northern Hemisphere falls on Monday, Sept. 22. If you want to be extra specific and mark it on your calendar, mark it for 11:19 a.m. PT.

Dates can shift slightly for equinoxes depending on the year, but it's always around this t

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