Indian Summer: What, Why, and When?

What Is an Indian Summer?

August 18, 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 early Algonquian Native Americans, 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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I believe here in IE we are having an Indian Summer!

It's 83 degrees and it's only 7pm, a few days ago or a week ago, it was so cold, even my dog wanted her thing you know we're back in high heat again. Today's high heat was in the 90s. (Inland Empire, Ca)

Indian Summer

Indeed, we would welcome Indian Summer. Here in the SW corner of Missouri, we skipped Fall altogether. 85 degrees and tornado followed by18 degrees and light snow two days later. We have leaves freezing on the trees and then falling.There are toads hopping into the house when the door is opened. Birds are pecking at the roof, desperate to get in. Squirrels are lodging in the attic. We anticipate Winter will be six months long. Hope we are wrong.

Indian Summer

We've had a wonderfully mild autumn so far in WNY, but cold has finally descended with snow showers and falling temps in the 20s. Hopefully, we'll still be able to enjoy our "Indian Summer" yet to come.

Indian Summer

We are certainly experiencing an Indian Summer here in the Pacific North West! We had a much colder October than usual and now have sunny days, chilly nights, beautiful sunsets and warm days with no wind, it is just simply delightful!


Indian Summer

Indian Summer? Fire Season? Here in the foothills of the Sierra mountains in No California rain just doesn't want to come around. Loving the 70 degree days and 40 degree nights, but we need rain so badly. Enough Indian's time for the rainy season!!!

indian summer

Here in Reno Nv, we are having a Indian Summer. The temps range from the high 60's to the low 30's. We had a small cold spell, then a high pressure system has set in, an we will not have a change in the pattern for a least for another week, am enjoying this Indian Summer

Indian Summer

Here in the Philadelphia area our daily high temps are not expected to go above the 30's/40's. Then, around the 23rd, our high is expected to be near the 60's. We often experience Indian Summer in mid-November in this geographical area. It is a beautiful experience.

Squaw Winter

What I learned from my mother agrees with this article. In her world, the early cold weather was referred to as “Squaw Winter”. We are VERY COLD in mid-Michigan, 20 deg. F, this morning, and recent scanty snowfall.

Indian summer

We haven’t had Indian summer yet in Illinois. Hopefully we will.

Indian Summer?YES!!

I live in Connecticut and it’s been pretty hot and humid here

Definitely an Indian summer

Definitely an Indian summer in Noethern California this year!

Indian Summer

Weather today (11/13/18) not Indian Summer here in Rochester, NY. Long range it looks like no Indian Summer this year.

IIndian Summer??

Rainy weather, is not "Indian Summer". & this is November 12 & it's pour rain here all day long. :'(


Indian summer as left june to aug month

No Indian Summer here this year!

NO Indian Summer this year! Lots of rain this fall. First time ever that I am so late storing my patio furniture because the weather was so yucky!
Lower Laurentians, QC

Indian Summer

We have had frost, debatable "Hard frost" Lovely warm day today, November 1st after chilly nights and dark, dim, sunless days on end.

Indian Summer 2018 - Central Indiana

Why no Indian Summer this year in Kokomo, IN

Indian Summer

We in southern Michigan have not had it either. Went right from hot summer to very cold days.

Indian Summer

Looked up Indian Summer in relation to British Isles . First mentioned in 1778 by Frenchman John De Crevecoeur , describing Fall Weather in Mohawk Country .

Winnipeg, winterpeg November 14th Indian summer

Today in Winnipeg the temperature was 41 degrees Fahrenheit and it met all the criteria for a beautiful sunny Indian summer day. The foot of snow that we had over the last two weeks was melting quickly great big puddles of water everywhere but the temperature this evening is now minus 4 degrees Celsius

Indian summer

I sure hope Cleveland, Ohio has not had Indian summer yet because that's when I get the Christmas lights done outside. Copd doesn't let me work on lights in the cold.

Indian Summer

I'm glad to see that November is when, of if, "Indian Summer" occurs. I'm old enough to remember when, here in Wisconsin, we had incredibly warm autumn weather back in the "60s. That usually occurred in October but even November & December could be unseasonably warm. But October 1963 had record warm temperatures in the 90s. Of course Ole' man winter followed with a vengeance after those unseasonably balmy periods. In fact decades after it occurred the older generation of locals talked about "the Armistice Day storm of 1940." That November 11th started as an unseasonably beautiful autumn day; duck hunters were out in force on the Mississippi River & the ducks kept coming in from the West. Those hunters were havin' a field day as more & more ducks flew into the river valley.
Those hunters didn't realize all those ducks were fleeing a monstrous storm front approaching from the West. When that storm front arrived on the Mississippi none of them were dressed for the violent change in weather. The barometric pressure that may have set a record low allowed this blizzard to descend with a vengeance on those hunters. Many of them, unable to reach the shore, froze to death. Those who survived learned a hard lesson: if the weather is almost to good to be true don't press your luck. I'm sure Native Americans would've perceived the incoming flocks of ducks for what it was & would've paddled their canoes to shore.

Indian Summers;

Thanks for this great story Ron; That November 11th started as an unseasonably beautiful autumn day; duck hunters were out in force on the Mississippi River & the ducks kept coming in from the West. Those hunters were havin' a field day as more & more ducks flew into the river valley. Those hunters didn't realize all those ducks were fleeing a monstrous storm front approaching from the West. When that storm front arrived on the Mississippi none of them were dressed for the violent change in weather. I agree with the Indian and canoe analogy; I have learned to predict certain weather patterns based on Leaf falling patterns in Autumn;

Indian Summer;

I surmise Indian Summer was the time of the year the American Indians would begin to gather Acorns + Beechnuts for Winter Storage; (I think they got the idea from the Squirrels and Chipmunks); I think I found some wild gooseberries today coincidentally here in Connecticut.

Indian Summer

Indian Summer is here in Aurora, CO. Beautiful warm days and very chilly nights. It has been this way since the hard freeze last week.

Indian Summer

October 8, 2017 - Tulsa, OK. - feels like Indian Summer - 70's and 80's for daytime highs and 40's and 50's at night.

Indian summer

We've had a few nights of below freezing in Montrose, CO but today the sun was out and warm. So our Indian summer is starting.

Indian summer in northern Indiana

I wonder if we are experiencing an indian summer. A few weeks ago it got down to the low 60s. We didn't have a hard frost but it did seem like it was going to start being cold. Now in October we are having 80 degree days and 50-60 degrees at night.

Indian Summer in New England

I would say here in New England(New Hampshire), we are having an Indian Summer. We have not had a cold spell, but some towns have had a few frosty mornings.
September 24 - 90 degrees, overnight in the low 60's.
September 25 - high 90's, overnight in the 60's.
September 26 - low 90's, overnight 65 degrees.

Indian Summer

I live in Michigan in the south East corner of the state, in Petersburg, near the Ohio border. I believe that we are experiencing Indian Summer right now. In the past few weeks it was nice cool weather now it is so sweltering hot we can hardly go out in it. I always remember my mom telling us that it was Indian Summer the second week after we went back to school in the fall September and that would be over in late October as a matter of fact around Halloween.