Indian Summer Engulfs the Northeast; Here's What that Means

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You hear the term "Indian summer" every fall, but do you know what it actually means?

ByBrian Donegan•October 6, 2017

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Parts of the Northeast will enjoy Indian summer through this weekend as a surge of above-average warmth engulfs the region.

Some areas of the interior Northeast experienced their first frost or first freeze of the season last weekend, and temperatures are now expected to reach the 70s and lower 80s at times through the upcoming weekend, generally 10 to 20 degrees above early-October averages.

(MORE: October 2017 Temperature Outlook)

First frost of the season at Sterling College in Vermont Oct. 1, 2017.
(thesterlingcollegefarm/Instagram)

For example, Old Forge, New York, in the Adirondack Mountains, saw a low of 26 degrees Sunday morning and reached a high in the 70s on Wednesday, with 70-degree-plus temperatures possible again this weekend and early next week. Bradford, Pennsylvania, dropped to 27 degrees Sunday morning and is expected to see highs in the 70s several days into early next week. 80s are even possible on Saturday in both locations.

(MAPS: 10-Day U.S. Forecast Highs/Lows)

The weather at these two locations is a prime example of Indian summer, a period of abnormally warm weather after the killing freeze of autumn.

Fall foliage in Victory, Vermont, in early October 2017.
(josh.a.blouin/Instagram)

A killing freeze occurs when the overnight low dips to 28 degrees or colder, and it may or may not occur with frost.

Indian summer typically occurs in mid- to late autumn and can occur more than once, according to the National Weather Service.

(MORE: Big Weather Changes You Can Expect in October)

The exact origins of the term "Indian summer" are uncertain, but some believe it is based on the warm and hazy conditions in the fall where Native American Indians chose to hunt in the upper Mississippi Valley west of the Appalachians.

A frosty morning at Jack Mountain Bushcraft School in northeast Maine Oct. 1, 2017.
(primitiveaddictions/Instagram)

In Europe, the equivalent of Indian summer is termed "Old Wives summer," or in poetry as "Halcyon Days."

In England, it is known as either "St. Martin's summer" or "St. Luke's summer," depending upon the date of occurrence.

Brian Donegan is a digital meteorologist at weather.com. Follow him on Facebook, Twitter and Instagram.