Astronomical Autumn 2021 Climate Summaries for La Crosse WI and Rochester MN

Astronomical Autumn 2021 (September 22 to December 20) was warmer with below-average precipitation at both La Crosse, WI and Rochester, MN.  

La Crosse, WI was 6°F warmer (3rd warmest) than the 1873-2021 long-term average (40.2°F). It was 2.03 inches drier than the 1873-2021 long-term average (5.79") for precipitation and 3.7" less than the 1897-2021 long-term average (10.2") for snowfall.  

Rochester, MN was 5.1°F warmer (5th warmest) than the 1886-2021 long-term average (37.5°F). It was 0.61" wetter than the 1886-2021 long-term average (5.35") for precipitation and 1.7" less than the 1933-2021 long-term average (12.3") for snowfall.

La Crosse WI...

Temperature...3rd Warmest

• During astronomical autumn, La Crosse Regional Airport had an average temperature of 46.2°F. This was 6°F warmer than the 1873-2021 long-term average of 40.2°F. This was the 3rd warmest autumn and the warmest autumn since 2015 (47.1°F - warmest). 4 of these 10 warmest autumns have occurred during the past 6 years (2015 - warmest, 2021 - 3rd warmest, 2016 - 6th warmest, and 2017 - 10th warmest). The table below lists the 10 warmest autumns in La Crosse, WI.

Ten Warmest Astronomical Autumns
     in La Crosse, WI
        1873-2021

         Average
Rank   Temperature   Year
----   -----------   ----
  1      47.1°F      2015
  2      47.0°F      1998
  3      46.2°F      2021
  4      46.1°F      2001
  5      45.7°F      1931
  6      45.5°F      2016
  7      44.7°F      1994
  8      44.6°F      1953
  9      44.4°F      1881
 10      44.3°F      2017

• The average high temperature was 55.6°F which was 6.9°F warmer than the 1873-2021 long-term average of 48.7°F. This was the 3rd warmest and the warmest since 2015 (56.0°F - warmest).
• The average low temperature was 36.9°F which was 5.2°F warmer than the 1873-2021 long-term average of 31.7°F. This was tied for the 6th warmest with 2016 and the warmest since 2016.  
   
• The warmest high temperature was 87°F on September 30.
• The coldest high temperature was 22°F on December 7.
   
• The warmest low temperature was 65°F on October 2.
• The coldest low temperature was 7°F on December 6 and December 8.

Precipitation...Drier-than-Average

• During astronomical autumn, La Crosse Regional Airport received 3.76" of precipitation. Which was 2.03" drier than the 1873-2021 long-term average of 5.79".  
   
• The wettest day occurred on November 11 when 0.76" fell.
   
• No precipitation fell on 52 days (57.8%).
• A trace of precipitation fell on 16 days (17.8%).
• Measurable (0.01" or greater) fell on 22 days (24.4%).

Snowfall...Below Average 

• During astronomical autumn, the official NWS snow observer near La Crosse Regional Airport received 6.5" of snow. This was 3.7" below the 1897-2021 long-term average of 10.2". 
   
• The snowiest day occurred on December 11 when 3" fell.
   
• No snow fell on 77 days (85.6%).
• A trace of snow fell on 8 days (8.9%).
• Measurable (0.1" or greater) fell on 5 days (5.6%).  

Snow Depth...Less than Average

• During astronomical autumn, the official NWS snow observer near La Crosse Regional Airport had an average snow depth of 0.2".  This was 0.6" below the 1893-2020 long-term average of 0.4". 
• The greatest snow depth was 5" on December 11 and December 12.

Rochester MN...

Temperature...5th Warmest

• During astronomical autumn, Rochester International Airport had an average temperature of 42.6°F. This was 5.1F warmer than the 1886-2021 long-term average of 37.5°F. This was the 5th warmest. 9 out of the 15 warmest autumns have occurred since 1998. The table below lists the 10 warmest autumns in Rochester, MN.

Ten Warmest Astronomical Autumns
     in Rochester MN
        1886-2021

         Average
Rank   Temperature   Year
----   -----------   ----
  1      43.9°F      2015
         43.9°F      2001
  3      43.6°F      1931
  4      42.7°F      1998
  5      42.6°F      2021
  6      42.0°F      2012
         42.0°F      1953
  8      41.9°F      2011
  9      41.8°F      1913
 10      41.3°F      2016

• The average high temperature was 52.0°F which was 5.1°F warmer than the 1886-2021 long-term average of 46.9°F. This was the 8th warmest and the warmest since 2015 (52.6°F - tied for 4th warmest with 1913 and 1918).  
• The average low temperature was 33.3°F which was 5.2°F warmer than the 1886-2020 long-term average of 28.1°F. This was the 5th warmest and the warmest since 2015 (35.2°F - warmest).
   
• The warmest high temperature was 85°F on September 26.
• The coldest high temperature was 18°F on December 7.
   
• The warmest low temperature was 60°F on October 2.
• The coldest low temperature was 2°F on December 6.

Precipitation...Slightly Drier-than-Average

• During astronomical autumn, Rochester International Airport received 4.74" of precipitation. Which was 0.61" drier than the 1886-2021 long-term average of 5.35". 
   
• The wettest day occurred on November 10 when 1.42" fell.
   
• No precipitation fell on 55 days (61.1%).
• A trace of precipitation fell on 12 days (13.3%).
• Measurable (0.01" or greater) fell on 23 days (25.6%).

Snowfall...Below Average

• During astronomical autumn, the official NWS snow observer near Rochester International Airport received 10.6" of snow.  This was 1.7" less than the 1933-2021 long-term average of 12.3".
   
• The snowiest day occurred on December 10 when 6.5" fell.
   
• No snow fell on 76 days (84.4%).
• A trace of snow fell on 8 days (8.9%).
• Measurable (0.1" or greater) fell on 6 days (6.7%).  

Snow Depth...Less than Average

• During astronomical autumn, the official NWS snow observer near Rochester International Airport had an average snow depth of 0.3". This was 0.5" less than the 1944-2021 long-term average of 0.8". 
   
• The greatest snow depth was 7" on December 11 and December 12.