Full Harvest Moon Friday Is Supermoon: What To Know In Napa Valley

NAPA VALLEY, CA — The harvest moon — the full moon nearest the autumnal equinox — always has a reputation as a stunner, but that will especially be the case with the last supermoon of the year Friday.

That’s if sky conditions in Napa Valley allow decent views of the moon. The National Weather Service currently predicts the skies over Napa Valley will be mostly clear Thursday night, partly cloudy Friday night and mostly clear Saturday night.

Musicians from the Tin Pan Alley Era to modern times have crooned about the harvest moon, and with good reason. The harvest moon is a favorite on the lunar calendar because the best times to view it are so reliable.

Normally, moonrise is about 50 minutes later each night of a full or nearly full moon phase. But the full harvest moon rises an average of 25 minutes later each night in the United States, according to The Old Farmer’s Almanac.

So, whether your musical tastes run from “Shine On, Harvest Moon” from the “Ziegfeld Follies” or Neil Young’s classic “Harvest Moon,” you should definitely plan to dance or otherwise play under it this weekend.

In Napa Valley, the moonrise is at 6:51 p.m. local time Thursday, 7:18 p.m. local time Friday and 7:46 p.m. local time Saturday. The moon appears full for a couple of days on either side of the actual full moon.

It reaches 100 percent illumination around 1 a.m. Pacific time Friday.

Combined, the supermoon effect — the point in its elliptical orbit when the moon is the closest to Earth, and what NASA calls a “moon illusion," a trick the brain plays on the mind in processing visual information — make the 2023 harvest moon worth getting outside to see.

The absolute best times to take in a view is when it appears over the horizon around midnight Thursday, Friday and Saturday. That’s when the “moon illusion,” as NASA calls it, kicks in.

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“Go out on the night of the full moon and find a good spot to watch it rise. It can be breathtaking, eliciting an awestruck ‘Wow!’ from any skywatcher,” NASA explains. “When we observe the Moon near the horizon, it often looks HUGE — whether it’s peeking over the shoulder of a distant mountain, rising out of the sea, hovering behind a cityscape, or looming over a thicket of trees.

“But here’s the thing: it’s all in your head. Really. …”

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The harvest moon doesn’t always rise in September, as it will this year. The harvest moon, a moniker assigned because it coincides with the fall harvest across North America, is the one that occurs closest to the autumnal equinox, which this year was on Saturday, Sept. 23.

The harvest moon is almost always in September, though there have been years when it has occurred in October. The moniker is a nod to the time of year when agricultural crops area ready for harvest. Before modern farm equipment, the harvest moon provided a few days of extra bright moonlight right after sunset for farmers to bring in their crops ahead of the first frost.

Sometimes, the harvest moon looks more orange, but that has nothing to do with it being a harvest moon.