Indian Summer: What, Why, and When?

What Is an Indian Summer?

November 3, 2020
Fall Road

In the fall, it seems that almost any warm day is referred to by most people as an “Indian summer.” And while their error is certainly not of the world-shaking variety, they are, for the most part, mistaken. Find out what a real Indian summer is!

What Is an Indian Summer?

Here are the criteria for a true Indian summer:

  • As well as being warm, the atmosphere during Indian summer is hazy or smoky, there is no wind, the barometer is standing high, and the nights are clear and chilly.
  • A moving, cool, shallow polar air mass is converting into a deep, warm, stagnant anticyclone (high pressure) system, which has the effect of causing the haze and large swing in temperature between day and night.
  • The time of occurrence is important: The warm days must follow a spell of cold weather or a good hard frost, but also be before first snowfall.
  • The conditions described above also must occur between St. Martin’s Day (November 11) and November 20. For over 200 years, The Old Farmer’s Almanac has adhered to the saying, “If All Saints’ (November 1) brings out winter, St. Martin’s brings out Indian summer.”

We rather enjoy this description written by Sandy Griswold for the Omaha Sunday World-Herald in November 1922:

I am enabled to say, however, that the characteristics of the season, when it appears in all its glory, are a mild and genial temperature, gentle southwestern breezes, unusual brightness of the sun, extreme brilliancy of the moon, a clear, blue sky; sometimes half hidden by a veil of gray haze; daybreaks redder than the splotch on the blackbird’s wing, and sunsets laden with golden fleeces, the wooded valleys aglow with the fires of richly tinted leaves, still clinging to the listless limbs, or lying where they have fallen….

Indian Summer

Why Is it Called an “Indian Summer”?

In parts of Europe, a similar phenomenon is known as an “Old Wives’ Summer” or “St. Martin’s Summer,” but how did the term “Indian summer” come to be? There are many theories.

Some say the term comes from Algonquian Native Americans located in what is now the northeastern United States, who believed that the condition was caused by a warm wind sent from the court of their southwestern god, Cautantowwit (“great spirit”).

Similarly, another origin states that Native Americans would routinely use this brief period of warm fall weather to gather a final round of supplies before winter’s hold set in.

Yet another possible origin involves European settlers in New England. Each year they would welcome the arrival of a cold wintry weather in late October when they could leave their stockades unarmed. But then came a time when it would suddenly turn warm again, and the Native Americans would decide to have one more go at the settlers. “Indian summer,” the settlers called it.

Watch a video from Almanac Editor-in-Chief Judson Hale about the origin of Indian Summer.

Indian Summer Recipes

Try our delicious Indian Summer Applesauce or Indian Pudding on your next Indian summer day.

Are you experiencing Indian summer conditions in your area? Let us know in the comments below!


The 1985 Old Farmer's Almanac


Reader Comments

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Indian Summer

I'm in the Northwest corner of CT and we have been having days in the 80's (October 17, 18 so far) I wouldn't mind if it lasted until December. :)

indian summer

My mother always said you can't have Indian Summer until you have Squaw Winter (frozen precipitation) Here in SE Mich we had graupel ( small weird shaped chunks of ice also called soft hail) on Nov 7th. We enjoyed several days in the 70s earlier a few days before. So according to Alice, we can now have an Indian summer.

Indian summer

The temp in Charlottesville today 11/05/15 was 78 degrees @ 4p.m. Frost occurred in October did we experience Indian Summer .


No it is in November

SW Michigan Indian Summer

We are certainly having an Indian Summer day on our homestead today, The Small House under a Big Sky in SW Michigan. It is 70, clear and our sky is a brilliant and bright blue. Our Lab Sassy is out on a blanket checking on a bone, our chickens are free ranging in the sunshine pecking at worms under the oak leaves. I am raking and cutting back perennials on our 5-acre property. I'll be eating lunch out under the trees soon. A glorious autumn day!!

Hudson Valley NY

We're having and going to have a great week here in the northeast with warm days of 70 degrees and then cool nights. Interesting cloud formations with blue and red skies, it will last all week into the weekend. Not sure if this is technically Indian Summer though, as it does not coincide with the dates given in the almanac.

Indian Summer

Had an Indian Summer last night in the mid North East. We had a cold spell for a few days and yesterday around 4:00 pm it gently blew in. I just stood on my porch for hours soaking it in until it was taken over with the chill of the evening. Praying it happens again tonight....we'll see