Frosty Tuesday AM: Fall color change accelerating

Freeze warnings out for northern Minnesota

20s in most of northern Minnesota Tuesday AM

Frost advisories out just north & west of the metro

30s in (especially northern) metro suburbs

Fall color change accelerating in Minnesota

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Source: Twin Cities NWS

Frosty start Tuesday:

Well it is mid-September after all.

The season’s coldest air mass is here, and the freeze is on “up north.”

Even some metro suburbs will see a touch of frost early Tuesday.

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Source: Twin Cities NWS

When it comes to plants there is a big difference between a light frost and a “hard freeze.” Many plants may survive a light frost, but several hours of temps below 28 degrees can freeze out sensitive annual plants.

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Source: NOAA

It’s hard to say we’re too far ahead of schedule with Tuesday’s frost/freeze. The average date for the 1st 32 degree temps at MSP in fall is October 7th. In the northern metro suburbs that’s closer to September 24th. But “average” is made up of extremes…so September 18th is definitely “in bounds” for frost in the north metro.

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Busy Saturday in Grand Marais harbor.

Image Credit: Paul Huttner – MPR News

Colors change accelerating:

Last Thursday I made the drive up to beautiful Grand Marais. I was a little surprised to see relatively few pockets of color along the way.

Different ball game on the way home Sunday.

I was pleasantly shocked at how fast the colors exploded along the ridges above Highway 61 and along I-35 north of Hinckley.

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Color splash along Highway 61 Sunday near Tofte.

Image Credit: Paul Huttner – MPR News

There are now splashes of yellow & red color all over the place, and the sumac are putting on a vibrant red show of red along I-35.

“Peak Color” ahead?

It seems many Minnesotans are enamored with the concept of finding the elusive “peak color” each year.

Defining…and finding “peak color” is a subjective art. Individual leaf peepers enjoy different intensity and types of color. Color changes can be highly localized and determined by drought stress, local temperature patterns and mix of trees & other vegetation.

When people ask me about finding peak color…my answer is usually the same. Just plane for the last two weeks of September or early October and enjoy the journey.

Often times leaf peeping is what you make of it…and I find that the colors seem to be spectacular just about every year in Minnesota.

I frequently post updated DNR fall color maps this time of year on Updraft.

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Source: MN DNR

Here’s another excellent resource for tracking fall color changes in the Superior National Forest.

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Source: USFS

Thanks to Steve Robertson form the U.S. Forest Service for the info.

Hi Paul:

I heard you mention the DNR fall color site the other day on my drive home, and I wanted share with you that there is also a fall color website for the Superior National Forest. It has current conditions, fall essays, and photos.

So far, phenology wise, this has been a weird color season. …It is pretty hard to write concise reports this year though, it is all over the board for levels of color. Even the tamaracks in some places are done, and they don’t even usually start until mid October.

Attached is the other very useful tool we use as a predictor.

Hope you had fun in Grand Marais.


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Thanks for saying more in one picture than I could in an entire post Steve. Do I get paid by the word?


  • Kelly

    Paul, I’m really surprised by the DNR map to see that a large section of the western Twin Cities is 25-50% color already. I’m in Washington County, just east of White Bear Lake. We still have only the slightest tinges of color – a few red leaves on the end of the sumacs, maybe, and a yellow cottonwood here and there. Why the discrepancy in such a small area? Does it have to do with moisture, or the lack thereof?