Saturday, September 01, 2012

Warm end to August continues above normal streak.. summer of 2012 ends up as 10th warmest/driest on record in Winnipeg


Daily temperature summary
for Winnipeg - August 2012
A warm end to August helped extend Winnipeg's streak of above normal monthly temperatures to an amazing 14 straight months.. the longest such period of warmth in the city since weather records began in 1872.  August finished with an average temperature of 19.3C at YWG airport, or 0.6C above the normal August mean of 18.7C (1981-2010 normal)  The month was actually cooler than normal through the 20th, but above normal temperatures over the last 10 days of the month, including 6 days of 30C or more (max of 35.4C on the 29th) helped to extend the above normal monthly temperature streak.


As a whole, the summer of 2012 finished with an average temperature of 19.8C for the 3 month period of June, July and August, about 1.5C above normal. This makes the summer of 2012 the 10th warmest on record in Winnipeg, tied with 4 other summers (1919, 1921, 1936 and 2006)  Records for Winnipeg started 140 years ago in 1872.

Top 10 warmest summers in Winnipeg (since 1872) 

 1.  1988 ....... 21.0C
 2.  1983 ....... 20.6C
 3.  1961 ....... 20.4C
 4.  1955 ....... 20.2C
 5.  1930 ....... 20.1C
 5.  1963 ....... 20.1C
 7.  1933 ....... 19.9C
 7.  1995 ....... 19.9C
 7.  1991 ....... 19.9C
10. 1919 ....... 19.8C
10. 1921 ....... 19.8C
10. 1936 ....... 19.8C
10. 2006 ....... 19.8C
10. 2012 ....... 19.8C

Normal summer average ... 18.4C  (1981-2010 average)


Summer rainfall in Winnipeg
June-August  2012. A wet start to the
summer turned dry by late June
 
August 2012 was also dry in Winnipeg with only 44 mm of rain for the month at YWG airport, about 30 mm below normal for the month (1981-2010 average of 79 mm)  This was the third straight month that was drier than normal, coming off a dry July (55 mm below average) and June (27 mm below average)  The total summer rainfall of 129.5 mm was over 100 mm below normal (248 mm based on 1981-2010 normals), and makes 2012 the 10th driest summer on record in Winnipeg. This comes on the heels of a very dry summer last year (93 mm) which ranked as the 5th driest summer of all time. To put this dryness into perspective, the total rainfall over the past two summers combined (222.5 mm) has been less than what we usually see in one typical summer (247.5 mm). Also interesting to note that three of Winnipeg's top 10 driest summers have occurred within the past 6 years. Could this be the start of a dry cycle in southern Manitoba after a prolonged wet cycle in the 1990s and early 2000s? Or is it just a couple of dry summers in nature's variable precipitation pattern?  Whatever the case, the summer rainfall pattern over the past decade in Winnipeg seems to be one that's either too wet or too dry..  

Top 10 driest summers in Winnipeg (since 1872)

 1.  1929 .........   76.7 mm
 2.  1886 .........   77.2 mm
 3.  1961 .........   91.0 mm
 4.  2006 .........   91.5 mm
 5.  2011 .........   93.0 mm
 6.  1889 .........   96.0 mm
 7.  1894 .........   97.1 mm
 8.  1915 ......... 114.8 mm
 9.  1936 ......... 121.4 mm
10. 2012 ......... 129.5 mm

Normal summer rainfall ....  247.5 mm (1981-2010 average)

For additional data and analysis of the warmth this year, consult "A Weather Moment" website. 

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