The heating season of 1998-1999 has been extraordinarily mild. This comes on the heels of last winter's unusual warmth. There are only two cases of back-to-back mild winters this century in the Minneapolis/St. Paul record in terms of Heating Degree Days for the July 1 to February 24th period. The other case occurred in the early 1930's.

Twin Cities Climate Record (1891-1999)

Top Ten Winters With the Fewest Heating
Degree Days (HDD) for the Period July 1
to February 24th.  Average HDD for this
interval 5824 based on 109 winters.

   Winter Season       HDD Total   Departure
                                   from average   
 1. 1930-31             4815         -1009    
 2. 1931-32             4895          -929
 3. 1920-21             4931          -893
 4. 1953-54             5005          -819
 5. 1918-19             5080          -744
 6. 1941-42             5083          -741
 7. 1998-99             5116          -708
 8. 1994-95             5121          -703
 9. 1997-98             5155          -669
10. 1986-87             5205          -619

Departures in terms of percentage range from
10.6 percent fewer HDD in the winter of 1986-87
to 17.3 percent fewer HDD in the winter of 
1930-31.  Note that only two back to back winters
are listed: 1930-31, 1931-32 and 1997-99, 1998-99.

Mark Seeley
Professor and Extension Climatologist
Department of Soil, Water, and Climate

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