During the meteorological summer of 2021 (June 1-August 31), average temperatures ranged from near-normal to 4 degrees above normal across the Upper Mississippi River Valley. The highest average temperature was 75.4°F at La Crosse Regional Airport. Meanwhile, the coolest average temperature was 65.3°F at Medford Taylor County Airport. August typically has average temperatures of 65 to 72°F.

This was the 2nd hottest summer (75.4°F) at La Crosse, WI. Only 1995 was warmer with an average temperature of 75.7°F. 6 out of the 17 hottest summers have occurred since 2010.  It was the 8th hottest summer (71.2°F) at Rochester, MN. It was the hottest summer since 2012 (72.4°F). 7 out of the 20 hottest summers have occurred since 2005.

The hottest temperature was 101°F at Postville, IA on June 6. This was the first 100°F or higher temperature in the Upper Mississippi River since May 15, 2013 (Austin, MN). Other 100°F temperatures occurred in Mondovi, WI on June 10 and near Theilman, MN on June 6 and June 11. Meanwhile, the coldest temperature was 35°F at Sparta Fort McCoy on June 22.

The summer rainfall was highly variable across the region. Rainfall totals ranged from 8.72" near Claremont, MN to 25.93" near La Crosse, WI. Typically rainfall ranges from 12 to 15 inches. It was the second wettest summer at La Crosse Regional Airport with 22.29" of rain. The previous record was 20.93" in 2010.

The summer began with abnormally dry (D0) and moderate drought (D1) covering much of the La Crosse Hydrologic Service Area. By mid-June, severe drought (D2) developed across parts of southeast Minnesota, northeast Iowa, and southwest Wisconsin. During July, above-normal rainfall gradually ended the abnormally dry (D0) and moderate drought (D1) across west-central, central, and north-central Wisconsin. In early August, extreme drought (D3) develop across northeast Iowa. This was the first time that this had been seen in the area since 2012. Above-normal rain in late August helped to end the drought across southeast Minnesota, and much of northeast Iowa and southwest Wisconsin.

Below are the meteorological summer 2021 climate summaries for La Crosse WI and Rochester MN.

La Crosse, WI

2021 Meteorological Summer was the Wettest and 2nd Hottest in La Crosse WI

During the meteorological summer (June 1st through August 31st) of 2021, it was the wettest summer (22.29" - the previous record was 20.93" in 2010) and the second hottest (75.4°F - only 1995 was hotter with an average of 75.7°F). Six out of the 17 hottest summers have occurred since 2010.

More details are listed below... 

Temperatures...

During meteorological summer, La Crosse Regional Airport had an average temperature of 75.4°F. This was 2.5°F warmer than the 1991-2020 normal of 72.9°F.  This made it the 2nd hottest summer.  Only 1995 (75.7°F) was hotter.  Six out of the 17 hottest summers have occurred since 2010.  They were 2010 (tied with 1983 and 2010 for 15th hottest), 2012 (6th hottest), 2016 (tied with 1983 and 2010 for 15th hottest), 2018 (5th hottest), and 2020 (4th hottest). The table below lists the ten hottest summers for the La Crosse Area.

    Ten Hottest Summers
      in La Crosse WI
         1873-2021

         Average 
Rank   Temperature    Year
----   -----------    ----
  1       75.7°F      1995
  2       75.4°F      2021
  3       75.3°F      1988
  4       74.7°F      2020
  5       74.5°F      2018
  6       74.4°F      2012
  7       74.2°F      1980
  8       74.0°F      1955
          74.0°F      1949
          74.0°F      1901

The table below provides a breakdown of the temperature departures from normal for La Crosse WI this summer...

        Summer 2021 Temperatures
             in La Crosse WI

                             Departure from
                                 Normal
                             --------------
June   Avg Temp     76.6°F  +5.6°F - Hottest
       Avg Max Temp 88.2°F  +6.5°F - 2nd Hottest
       Avg Min Temp 64.9°F  +4.5°F - Hottest

July   Avg Temp     75.4°F  +0.4°F 
       Avg Max Temp 85.6°F  +0.2°F 
       Avg Min Temp 65.2°F  +0.7°F 

August Avg Temp     74.3°F  +1.5°F - Tied for 11th Hottest
       Avg Max Temp 84.6°F  +1.4°F - Tied for 18th Hottest
       Avg Min Temp 63.9°F  +1.6°F - 18th Hottest

Summer Avg Temp     75.4°F  +2.5°F - 2nd Hottest
       Avg Max Temp 86.1°F  +2.6°F - Tied for 3rd Hottest
       Avg Min Temp 64.6°F  +2.2°F - Tied for 2nd Hottest

Other temperature tidbits this summer...

• The hottest temperature was 99°F on June 5 and June 10.
• The coldest high temperature was 70°F on June 21. 
   
• The coldest temperature was 49°F on June 22.
• The warmest low temperature was 79°F on July 5.
   
• The temperature climbed to or exceeded 90°F on 29 days. Normally, there are 15 days per summer. This was the 8th most in a meteorological summer. This was the most since 2012 (32 days). The greatest number was 41 days in 1988.
• Temperatures averaged above normal on 58 days, below normal on 29 days and normal on 5 days.

Rainfall...

During the meteorological summer, La Crosse Regional Airport received 22.29" of rain. This was 9.08" wetter than the 1991-2020 normal of 13.21". This made it the wettest summer. The previous record was 20.93" in 2010. 

The table below lists the ten wettest summers for the La Crosse Area.

    Ten Wettest Summers
      in La Crosse WI
         1873-2021
         
Rank   Rainfall    Year
----   --------    ----
  1  22.29 inches  2021
  2  20.93 inches  2010
  3  20.32 inches  2007
  4  20.12 inches  1990
  5  19.88 inches  1993
  6  19.82 inches  1981
  7  19.38 inches  1899
  8  19.24 inches  2016
  9  18.08 inches  1928
 10  17.89 inches  1953

This was the 6th consecutive summer with above-normal rainfall.

The table below contains the monthly rainfall totals and their departures from normal for this summer.

         Summer 2021 Rainfall
            in La Crosse WI

                           Departure
   Month    Rain Total    from Normal
   -----    ----------    -----------
   June     5.30 inches   +0.22 inches 
   July     5.21 inches   +0.98 inches 
   August  11.78 inches   +7.88 inches - 2nd Wettest
 
   Summer  22.29 inches   +9.08 inches - Wettest

Other rainfall tidbits this summer...

• The La Crosse area was in moderate (D1) drought for much of June and abnormally dry (D0) during July.
• The wettest day occurred on August 7 when 5.59" of rain fell. This was the wettest calendar day.  The previous record was 5.55" on September 6, 1884.

Measurable rain fell on 31 days (33.7%) and trace amounts fell on another 8 days (8.7%).  

• 0.01 inches or more - 31 days
• 0.10 inches or more - 20 days
• 0.50 inches or more - 10 days
• 1.00 inches or more -  8 days

Sky...

• It was clear on 62 days.
• It was partly cloudy on 28 days.
• It was cloudy on 2 days.

Sea Level Pressure...

• Highest was 30.27 inches on August 14.
• Lowest was 29.45 inches on June 20. 

Winds...

• Highest sustained wind was 33 mph from the southeast on June 17.
• Highest wind gust was 47 mph from the northwest on June 17.

Rochester MN

2021 Meteorological Summer Had Its 8th Hottest and It was Drier-than-Normal in Rochester MN

During the meteorological summer (June 1st through August 31st) of 2021, Rochester had its 8th hottest summer with an average temperature of 71.2°F. 7 out of the 20 hottest summers have occurred since 2005. A total of 12.33" of rain fell. This was 1.33" drier than normal.

More details are listed below... 

Temperatures...

During meteorological summer, Rochester International Airport had an average temperature of 71.2°F. This was 2.5°F warmer than the 1991-2020 normal of 68.7°F.  This made it the 8th hottest summer. 7 out of the 20 hottest summers have occurred since 2005.  The table below lists the 10 hottest summers for the Rochester Area.

    Ten Hottest Summers
      in Rochester MN
         1886-2021

         Average 
Rank   Temperature    Year
----   -----------    ----
  1       73.0°F      1949
  2       72.4°F      2012
  3       72.2°F      1988
          72.2°F      1955
  5       71.8°F      1936
  6       71.7°F      1931
  7       71.4°F      1943
  8       71.2°F      2021
  9       71.1°F      1995
          71.1°F      1983

The table below provides a breakdown of the temperature departures from normal for Rochester MN this summer...

        Summer 2021 Temperatures
             in Rochester MN

                             Departure from
                                 Normal
                             --------------
June   Avg Temp     73.0°F  +5.5°F - 2nd Hottest
       Avg Max Temp 84.7°F  +7.1°F - 3rd Hottest
       Avg Min Temp 61.3°F  +3.8°F - Tied with 2018
                                    for 2nd Hottest

July   Avg Temp     71.4°F  +0.9°F 
       Avg Max Temp 81.5°F  +1.2°F  
       Avg Min Temp 61.3°F  +0.5°F 

August Avg Temp     69.1°F  +0.9°F
       Avg Max Temp 79.2°F  +1.2°F
       Avg Min Temp 59.0°F  +0.7°F 

Summer Avg Temp     71.2°F  +2.5°F - 8th Hottest
       Avg Max Temp 81.8°F  +3.2°F
       Avg Min Temp 60.5°F  +1.7°F - Tied with 1943
                                    and 2018 for the
                                    10th Hottest

Other temperature tidbits this summer...

• The hottest temperature was 95°F on June 5 and June 10.
• The coldest high temperature was 66°F on June 21. 
   
• The coldest temperature was 46°F on June 21. 
• The warmest low temperature was 71°F on July 11.
   
• The temperature reached 90°F on 10 days.  Normally there are 4 days.
• Temperatures averaged above normal on 53 days, below normal on 29 days, and normal temperatures on 9 days.

Rainfall...

During the meteorological summer, Rochester International Airport received 12.33" of rain. This was 1.33" drier than the 1991-2020 normal of 13.66 inches.  

The table below contains the monthly rainfall totals and their departures from normal for this summer.

         Summer 2021 Rainfall
            in Rochester MN

                           Departure
   Month    Rain Total    from Normal
   -----    ----------    -----------
   June     1.46 inches   -3.89 inches - 8th Driest
   July     4.13 inches   -0.06 inches 
   August   6.74 inches   +2.62 inches - 7th Wettest
 
   Summer  12.33 inches   -1.33 inches 

Other rainfall tidbits this summer...

• The Rochester area was in moderate (D1) drought for most of the summer.  
• The wettest day occurred on August 27 when 3.51" of rain fell. 

Measurable rain fell on 28 days (30.4%) and trace amounts fell on another 5 days (5.4%).

• 0.01 inches or more - 28 days
• 0.10 inches or more - 18 days
• 0.50 inches or more - 10 days
• 1.00 inches or more -  2 days

Sky...

• It was clear on 63 days.
• It was partly cloudy on 26 days.
• It was cloudy on 3 days.

Sea Level Pressure...

• Highest was 30.30 inches on August 14.
• Lowest was 29.49 inches on June 20.  

Winds...

• Highest sustained wind was 38 mph from the south on August 28.
• Highest wind gust was 60 mph from the south on August 28.