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I must confess I’m positively giddy about the weather for the next couple of days, which coincides with the start of fall and the Harvest Moon.

The Harvest Moon is the closest full moon to the autumnal equinox, and is aptly named for the added light given to farmers harvesting their summer crops. The Harvest Moon’s arrival can vary by about two weeks, but this year it is occurring very close to the actual start of autumn.

This year the weather is going to be particularly clear as the Harvest Moon clears the horizon at 7:07 Monday evening ― making for some fantastic photographs. The moon is officially full at 7:54 p.m. Monday evening but when it rises Tuesday evening it’s still 99.8 percent full, and 98.3 percent full when it rises the following night. This gives the appearance of three or even four nights of a full moon, all rising at nearly the same time each night.

The percentage of cloud cover is forecast to be near zero at dusk Monday.
The percentage of cloud cover is forecast to be near zero at dusk Monday.WeatherBELL

Typically the moonrise shifts about 50 minutes later each day. However, in autumn, there’s only about a 20 to 25 minute difference between successive moon rise times. Each subsequent rise is also further north. This evening, the moon will clear the horizon south of due east, it will be nearly perfectly east on Tuesday, and north of due east by Wednesday.

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A Harvest Moon rose over the State House in Boston on Monday.
A Harvest Moon rose over the State House in Boston on Monday.Matthew J. Lee/Globe Staff

Of course while the moon is traveling around the earth at 2,288 miles an hour, the Earth is traveling around the sun at a whopping 67,000 miles per hour, and in the process we are going from nearly 15 hours of daylight in late June all the way down to around 9 on the winter solstice. With the autumnal equinox occurring on Sept. 22nd, the angle of the sun at noon today is equivalent to March 21st. Of course the big difference between the sun in March and the sun now is that each day in the spring it’s getting a little stronger, and each day this time of the year it’s getting a little weaker.

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Plants and animals are all responding to the loss of light and the noticeable splash of color will continue to overspread the region in the next several weeks. This is also the time of year you should be treating any house plants that you put outside for insects before moving them back in.

There are seven days left when the amount of daylight will exceed the night. Starting Monday Sept. 27th, with just under 12 hours between sunrise and sunset, the nights will overtake the days and this will of course last for another 6 months.

A Harvest moon rose above Plymouth Harbor framed through the masts of the Mayflower ll ship.
A Harvest moon rose above Plymouth Harbor framed through the masts of the Mayflower ll ship.John Tlumacki/Globe Staff