Extreme Temperature Julys Are Becoming More Commonplace Across Southeast Lower Michigan

In the past five years, three Julys have placed on the top 20 warmest Julys while two have placed on the top coolest! And out of those; three have placed in the top six coolest or warmest Julys. So, basically it's been feast or famine lately for July temperatures over Southeast Lower Michigan.

June and July's temperature statistics are in across Southeast Lower Michigan and while cool, not terribly so. Actually June was above normal so it's really July that we have to contend with...

JULY'S COOL TEMPERATURES
 
DETROIT

AVG. MAXIMUM     79.9              83.4    -3.5
AVG. MINIMUM     59.9              63.9    -4.0
MEAN             69.9              73.6    -3.7    8TH COOLEST
DAYS MAX >= 90      1               4.5    -3.5

FLINT

AVG. MAXIMUM     79.1              81.9    -2.8
AVG. MINIMUM     57.5              59.2    -1.7
MEAN             68.3              70.5    -2.2    9TH COOLEST
DAYS MAX >= 90      0               2.8    -2.8

SAGINAW

AVG. MAXIMUM     78.4              81.8    -3.4
AVG. MINIMUM     58.4              60.2    -1.8
MEAN             68.4              71.0    -2.6    11TH COOLEST
DAYS MAX >= 90      0               3.0    -3.0

SOUTHEAST LOWER MICHIGAN /3 CLIMATE SITES/

 

DTW  FNT  MBS   AVE NOR DEP

69.9 + 68.3 + 68.4 = 68.9 - 71.7 = - 2.8   ~  10TH COOLEST

LAST TIME THIS COOL OR COOLER: 2009

68.9 + 65.6 + 66.0 = 66.8 - 71.7 = - 4.9   ~  2ND COOLEST

 

 

So as you can see while cool this July, it was nowhere as cool as in 2009 which was Detroit's 3rd coolest July and Flint and Saginaw's coolest of all record time. One of the main reasons it felt so cool this July is that we are coming down off two back to back hot Julys; 2011 & 2012! Last July /2013/ averaged slightly above normal.

 

Rank	Detroit Area*				Flint Bishop**				Saginaw Area***
	Coldest		Warmest		Coldest		Warmest		Coldest		Warmest
	Temp	Year	Temp	Year	Temp	Year	Temp	Year	Temp	Year	Temp	Year
1	67.1	1891	79.3	2011	65.6	2009	78.0	1921	66.0	2009	77.5	1921
2	68.8	1992	79.0	1955	66.9	1992	77.7	1935	66.2	1992	76.8	1916
3	68.9	2009	79.0	2012	67.3	1967	76.8	2011	67.1	1924	76.4	2012
4	68.9	1967	79.0	1921	67.3	1962	76.7	1934	67.2	1920	76.2	1935
5	69.6	1971	77.9	1916	67.4	1971	76.5	1955	67.3	1945	76.1	2011
6	69.6	1875	77.7	1931	67.4	1960	76.1	2012	67.5	1962	76.0	1931

Even more notable in the recent past since the millennium, eight out of 15 Julys (including July 2000) placed either in the top 20 coolest or warmest July listings at all three climate sites! Therefore just over half of the last 15 Julys /53%/ made the top 20 lists. Extraordinary when you consider records go back into the early 1900s at Flint and Saginaw and 1870s in Detroit! In additions; temperature deviations during the summer months are less wide or exaggerated by nature. The hotter Julys have it over the cooler ones thus far; about 5 to 3 in the past 15 years anyway.

Top 20 Coldest/Warmest Julys in Southeast Lower Michigan   Rank Detroit Area* Flint Bishop** Saginaw Area*** Coldest Warmest Coldest Warmest Coldest Warmest Temp Year Temp Year Temp Year Temp Year Temp Year Temp Year 1 67.1 1891 79.3 2011 65.6 2009 78.0 1921 66.0 2009 77.5 1921 2 68.8 1992 79.0 1955 66.9 1992 77.7 1935 66.2 1992 76.8 1916 3 68.9 2009 79.0 2012 67.3 1967 76.8 2011 67.1 1924 76.4 2012 4 68.9 1967 79.0 1921 67.3 1962 76.7 1934 67.2 1920 76.2 1935 5 69.6 1971 77.9 1916 67.4 1971 76.5 1955 67.3 1945 76.1 2011 6 69.6 1875 77.7 1931 67.4 1960 76.1 2012 67.5 1962 76.0 1931 7 69.7 1920 77.1 1988 67.5 2000 76.1 1931 67.5 1956 75.9 1955 8 69.9 2014 76.8 1999 67.6 1996 75.9 1936 67.8 1950 75.9 1936 9 69.9 1924 76.8 1901 68.3 2014 75.8 1933 67.9 2000 75.8 1988 10 69.9 1884 76.6 2010 68.3 1950 75.5 1987 68.2 1965 75.5 1934 11 70.2 2000 76.5 2002 68.4 2004 75.2 1988 68.4 2014 75.3 1933 12 70.3 1882 76.5 1952 68.4 1965 74.9 2002 68.4 1985 74.3 2010 13 70.4 1979 76.2 1949 68.6 1956 74.5 1949 68.5 2004 74.2 1930 14 70.4 1965 76.2 1935 68.6 1968 74.5 1939 68.6 1981 74.1 1983 15 70.4 1915 76.1 2006 68.6 1945 74.2 2010 68.6 1925 74.1 1937 16 70.4 1895 76.0 1987 69.0 1969 74.0 1983 68.7 1947 73.9 1987 17 70.6 1996 75.9 1964 69.1 1947 73.8 1977 68.8 1979 73.5 2006 18 70.6 1978 75.9 1887 69.2 1924 73.7 1938 68.8 1915 73.5 2002 19 70.7 1984 75.7 1977 69.4 1997 73.5 1952 69.1 1978 73.3 1998 20 70.7 1945 75.5 1993 69.4 1954 73.4 1940 69.1 1951 73.3 1966 * Detroit Area temperature records date back to January 1874.

Another thing I'll throw out there while on the subject of top 20 lists; the top 20 lists have also been busy in the winter for coldest/warmest months and snowfall. Why? One thing is a more amplified upper jet stream, more blocking and stormier pattern. Global climate change or natural cyclical climate pattern changes /NAO, AO, PDO, AMO, EL NINO, LA NINA,  MJO/ or some of both? Since it is such a short trend where climate change is concerned, I lean more on the side with natural cyclical changes in regard to the past 15 years. Time will tell....     Making weather fun while we all learn, Bill Deedler -SEMI_WeatherHistorian