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The last time there was a full moon on Halloween across all time zones in United States, the nation was still engaged in World War II. Now it looks like the stars – and the clouds – are aligning to allow most Americans to enjoy some added ambiance on October 31, even if their trick-or-treat plans have been disrupted by the pandemic.

The last time a Halloween full moon occurred in all U.S. time zones was in 1944, according to the Farmer’s Almanac. Some time zones saw a full moon on Oct. 31, 2001.

The next one won’t happen until 2039, NASA said.

Most Americans hoping to take in the celestial event are in luck. The National Weather Service suggests a low likelihood of precipitation across nearly the entire country on Saturday.

NWS maps projecting cloud cover percentage indicate that clouds could obscure the full moon across the Great Lakes region. Areas in the South and Pacific Northwest will see some level of cloud cover, but likely not enough to fully block out the moon.

Coastal Los Angeles County is expected to see some patchy low clouds late at night in the morning hours this weekend, but much of Southern California will experience mostly clear skies through Saturday, according to the weather service’s forecast.

“The forecast calls for the cloudiest skies over Michigan, Wisconsin, and Minnesota. Scattered clouds across the Mid-Atlantic, Southeast, and Gulf coast states could add to the spookiness as they pass in front of the full moon. The rest of the nation should enjoying seeing the rare full moon on this Halloween,” says News Nation Meteorologist Gerard Jebaily.

Although Saturday’s moon will be a blue moon, it won’t actually appear to be blue. Scientists use the term to describe the second full moon of a given month, which only occurs about once every 2 1/2 years, NASA said.

According to the Farmers Almanac, the first full Moon of 2020 howled onto the scene with January’s Wolf Moon on Jan. 10. And usually, we have one for each month, making the total 12 for the year. But on occasion, some months will have two full Moons.

That’s the case this month. There was a full Moon on Oct. 1, known as the Harvest Moon, which usually appears in September. It is so named because it occurs closest to the autumnal equinox. The Sept. 2 full moon occurred too early to be known as the harvest moon.

The second is coming up on Oct. 31 — a Halloween Blue Moon. It is also called the Hunter’s Moon because it usually occurs in October, the month when traditionally game was fattened and preparations for winter began.

This year’s Blue Moon, which will turn full at 10:49 a.m. EDT, will be a rare Halloween treat.