For the first time since records have been kept, Pierre has failed to reach 100F in back to back summers. 

The highest temperature recored at Pierre during the summer of 2009 was 97F - most recently on August 12.  The highest temperature recorded in 2008 was 99F on August 30th.  In an average summer, Pierre would normally record a high temperature at or above 100F about 9 times. In addition, since 1933, there has only been one other year (1993) when temperatures have failed to reach 100F.  Thus, failing to reach this temperature milestone in two consecutive summers is quite a rare event.  Temperature records date back to 1933 in Pierre.        

A summary of the temperature trends in 2009 indicated that the number of calendar days when high temperatures exceeded 90F, 95F or 100F at Pierre, Aberdeen, and Watertown were well below climatological averages (see listings below) and very much mimicked the trends from the cool summer of 2008. 

Listed below are the dates when the temperatures last reached 100F at selected cities in the NWS Aberdeen Forecast area:

• Aberdeen (102F):  July 7, 2007 
• Pierre (101F): - September 4, 2007
• Watertown (100F): July 7, 2007  
• Mobridge (100F): - August 13, 2007
• Wheaton (100F): - July 8, 2007  

 ABERDEEN (1893-2008) - AVG NUMBER OF DAYS IS BASED ON 30 YEAR NORMALS (1971-2000) 

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 100F: 2.3

2009....0

2008....0

2007....1
2006....5
2005....0
2004....0

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 95F:  7.7
2009....1

2008....0
2007....4
2006....10
2005....3
2004....0

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 90F: 20.5

2009....6

2008....10
2007....13
2006....17
2005....14
2004....2

RECORD HOTTEST TEMPERATURE:              115 F (7/9/1936)

                                               (7/6/1936)
YEAR WITH THE MOST 100F TEMPERATURES:    1936 - 35 DAYS 
YEAR WITH THE MOST 95F TEMPERATURES:     1936 - 44 DAYS 
YEAR WITH THE MOST 90F TEMPERATURES:     1936 - 69 DAYS 
EARLIEST 90F TEMPERATURE:                4/4/1921
LATEST 90F TEMPERATURE:                  10/16/1991
EARLIEST 100F TEMPERATURE:               5/1/1959
LATEST 100F TEMPERATURE:                 9/22/1936

 PIERRE (1933-2008)  - AVG NUMBER OF DAYS IS BASED ON 30 YEAR NORMALS (1971-2000) 

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 100F:  8.8

2009.....0

2008.....0
2007.....10
2006.....14
2005.....14
2004.....4

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 95F:  21.6
2009.....7

2008.....5
2007.....20
2006.....37
2005.....32
2004.....16

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 90F: 42.7
2009.... 21

2008.....19
2007.....44
2006.....60
2005.....53
2004.....32

RECORD HOTTEST TEMPERATURE:               117 F (7/15/2006)
YEAR WITH THE MOST 100F TEMPERATURES:     1936 - 41 DAYS
YEAR WITH THE MOST 95F TEMPERATURES:      1936 - 58 DAYS
YEAR WITH THE MOST 90F TEMPERATURES:      1936 - 79 DAYS
EARLIEST 90F TEMPERATURE:                 4/9/1976
LATEST 90F TEMPERATURE:                   10/29/1933
EARLIEST 100F TEMPERATURE:                5/8/1934
LATEST 100F TEMPERATURE:                  9/26/1974

WATERTOWN (1893-2008)  - AVG NUMBER OF DAYS IS BASED ON 30 YEAR NORMALS (1971-2000) 

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 100F:  0.8

2009.....0

2008.....0
2007.....1
2006.....4
2005.....0
2004.....0

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 95F:  4.9
2009.....0

2008.....0
2007.....3
2006.....7
2005.....4
2004.....0

AVG NUMBER OF DAYS WITH TEMPERATURES AT OR ABOVE 90F: 14.9
2009.....3

2008.....4
2007.....13
2006.....17
2005.....14
2004.....2

RECORD HOTTEST TEMPERATURE:                110 F (7/20/1934)
YEAR WITH THE MOST 100F TEMPERATURES:      1933 - 17 DAYS
YEAR WITH THE MOST 95F TEMPERATURES:       1936, 1933 - 34 DAYS
YEAR WITH THE MOST 90F TEMPERATURES:       1933 - 53 DAYS
EARLIEST 90F TEMPERATURE:                  4/2/1910
LATEST 90F TEMPERATURE:                    10/5/1963
EARLIEST 100F TEMPERATURE:                 5/28/1934
LATEST 100F TEMPERATURE:                   9/10/1931

 Mike Fowle - Science and Operations Officer