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An illustrated guide to the signs of Minnesota fall

Summer is taking its leave.

On Sunday evening, the temperatures dropped and the wind picked up, rattling the leaves on the trees. It felt as though fall had arrived in the space of a day.

Minnesotans can expect to see a lot more signs of fall in the coming weeks, according to data from the Minnesota Phenology Network. This group of naturalists record the timing of seasonal flora and fauna events across the state of Minnesota. The group formed in 2010 and compiles reports from independent observers, with some records going back to the 1940s.

MinnPost analyzed the network’s dataset to find average dates of the signs of autumn in Minnesota. Because the date when natural phenomena happen can vary wildly by location, even in the same year, we’ve limited our analysis to observations in the 16- county Twin Cities metro area and to phenomena that have three or more recorded observations over time.

All illustrations by Greta Kaul.

Showy goldenrod blooms

Solidago speciosa
September 1

These tall, sunny flowers are harbingers of fall. They're often mistakenly blamed for allergies that are actually brought on by ragweed. Look for them in sunny areas with dry soil.

Earliest observation: August 12 (1988)
Latest observation: September 20 (1975)

Flowering nodding Bur-marigold

Bidens cernua
September 1

These little yellow flowers are found in shady, wet areas, like swamps and near shorelines.

Earliest observation: August 19 (1979)
Latest observation: September 9 (1977)

Paper birches turn

Betula papyrifera
September 21

The leaves of the most iconic birch variety turn golden yellow mid-autumn. These trees are found across most of Minnesota.

Earliest observation: August 8 (2012)
Latest observation: November 5 (2013)

Muskrat houses appear

Ondatra zibethicus
September 27

Muskrats make their homes by piling up plants and mud into mounds in wet areas. They spend much of the winter in these dens, which have underwater entrances and can include many rooms.

Earliest observation: September 16 (1984)
Latest observation: October 14 (1990)

Red maples turn

Acer rubrum
September 27

Some of the first trees to exhibit fall colors are red maples, according to Minnesota Phenology Network data. The leaves turn bright red.

Earliest observation: April 25 (2013)
Latest observation: November 4 (2013)

White oaks turn

Quercus alba
September 19

These central and southeastern Minnesota natives drop their acorns and the leaves turn color around mid-September.

Earliest observation: April 29 (2013)
Latest observation: November 12 (2013)

Quaking aspens turn

Populus tremuloides
September 30

The leaves of this aspen, found across Minnesota, turn a golden yellow in the fall.

Earliest observation: August 14 (2015)
Latest observation: November 1 (2011)

Tamaracks turn

Larix laricina
October 18

Found in boggy areas, tamarack trees resemble pines, but they’re actually larches. Unlike pines though, which are evergreens, tamaracks turn a brilliant yellow in the fall. They're usually in full color by mid-October, according to the data.

Earliest observation: September 25 (2009)
Latest observation: October 29 (2010)

Leaves have fallen

Early November

According to the dataset, the dropping of leaves, which tends to begin in mid-September and continues throughout the fall, is typically complete by the first week of November. When leaves drop varies by tree species.

All data supplied by the Minnesota Phenology Network and its volunteers. For more information about the network, visit