Happy Autumn: Summer was warmest on record for Twin Cities

Streak of warmer than average temperatures hits 7 months. October outlook favors warmer than average temperatures.

30-day temperature outlook
30-day temperature outlook for October 2021.
NOAA Climate Prediction Center

Happy Autumn 2021 Minnesota.

The vernal equinox at 2:20 p.m. Wednesday marks the start of astronomical autumn.

613 seasons_solstice_equinox_NASA
Seasons.
NASA

Here are a few interesting tidbits about our autumnal equinox in Minnesota.

  • The sun is at about 45 degrees above the southern horizon now at solar noon.

  • Minnesota is now getting the same amount of solar energy as March 21.

  • The sun rises and sets almost directly due east/west this time of year.

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Seasonal sunset directions.
Illustration courtesy of SkyandTelescope.com.

Warmest meteorological summer on record

2021 was the warmest meteorological summer on record for many Minnesota locations including the Twin Cities, Brainerd and Duluth. We nearly set the statewide warmest summer on record.

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Mark Seeley elaborates in this Weather Talk post.

If we look at the statewide mean monthly temperatures for June through August, 70.6°F, this trails only the summer of 1988, 70.7°F on a statewide basis for hottest summer in state history. For some individual climate stations, 2021 brought the hottest summer in their climate history, including MSP, Duluth, Brainerd, Grand Rapids, Roseau, and Park Rapids.

It’s also interesting to note the wide geographical differences in summer rainfall across Minnesota’s climate divisions.

Minnesota summer temperature and precipitation rankings
2021 Minnesota summer temperature and precipitation rankings.
Mark Seeley

Warm streak hit 7 months

September is running 2 degrees warmer than average in the Twin Cities as we approach the last week of this month. This marks the 7th straight month of warmer than average temperatures in the Twin Cities and much of Minnesota. Here’s are the numbers for the Twin Cities compared to the average since March.

  • March +7.2 degrees

  • April +0.6 degrees

  • May +0.7 degrees

  • June +7.2 degrees

  • July +1.7 degrees

  • August +2.2 degrees

  • September +2.0 degrees

Overall our temperatures have been about 3 degrees warmer than average in the Twin Cities since March 1. That’s closer to the average climate for Des Moines, Iowa.

Warm October?

The National Oceanic and Atmospheric Administration’s monthly climate outlook for October favors warmer than average temperatures overall across the Midwest.

30-day temperature outlook
30-day temperature outlook for October 2021.
NOAA Climate Prediction Center

It also slightly favors wetter than average conditions across most of Minnesota.