The first freeze of the season may be here before you know it.

In fact, some parts of the northern Plains and Rockies have already had their first freeze, as well as accumulating snow.

But when does the first freeze typically occur? Below, we'll break it down by the approximate average date.

Keep in mind, however, that these are average dates. Different weather conditions each year can make the first freeze occur earlier or later (sometimes much earlier or later) than what is shown in a given region.

Sept. 15

The average first freeze occurs sometime around Sept. 15 for much of the Rockies and Intermountain West, as well as parts of the northern Plains and Upper Midwest (closer to the international border). Some inland areas of the upper Great Lakes also see their first freeze around Sept. 15.

Maine's Mahoosuc Range, New Hampshire's White Mountains, Vermont's Green Mountains and New York's Adirondack Mountains drop to the freezing mark around Sept. 15, as well, mainly in the highest peaks.

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Oct. 1

A large swath of the West and Midwest sees their first freeze sometime near Oct. 1. This includes much of the Great Basin, northern Plains, upper Midwest and parts of the upper Great Lakes.

In the Colorado Plateau in northern Arizona and the Sangre de Cristo Mountains in northern New Mexico, the average first freeze occurs around Oct. 1 over the highest elevations. The lower elevations usually stay above 32 degrees for a couple extra weeks.

Most of the Adirondacks and Catskills in New York experience 32-degree temperatures around Oct. 1, along with the Appalachians from west-central Pennsylvania down into eastern West Virginia.

The majority of New England also gets its first freeze around Oct. 1, on average. The exception is areas closer to the coast, which don't see it until a couple weeks later.

Oct. 15

A large area of the country averages the first freeze in mid-October.

Parts of the northern Southwest, much of the central Plains, parts of the upper and mid-Mississippi Valley, much of the Great Lakes, the northern Ohio Valley and a large swath of the Northeast generally reach 32 degrees around Oct. 15.

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The Great Smoky Mountains in eastern Tennessee and western North Carolina also have their first freeze near Oct. 15, as well as the Shenandoah Valley of western Virginia and much of West Virginia.

Nov. 1

Parts of the Southwest, southern Plains, mid-Mississippi and Ohio Valleys, and mid-Atlantic don't see their first freeze, on average, until Nov. 1.

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The major cities along the Interstate 95 corridor, from New York City to Philadelphia, Baltimore and Washington D.C., are included in not seeing 32-degree temperatures until about Nov. 1. This is due to the urban heat island effect , keeping cities warmer than their suburbs overnight.

Nov. 15

Parts of Southern California, the Southwest, southern Plains, lower Mississippi Valley and Southeast don't see their first freeze until Nov. 15, on average.

The southernmost portions of these regions may not see 32-degree temperatures at all, such as southeastern Texas, Louisiana, southern Mississippi and Alabama, the coastal Carolinas, southern Georgia and all of Florida.