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... Extremely High Dewpoints During Meteorological Summer...
The meteorological summer /June through August/ will most certainly
be remembered not so much for record breaking heat /there were very
few record high temperatures set across the area/...but a stifling
combination of heat and humidity that kept coming in waves. The
humidity...in particular...made for many uncomfortable afternoons
across the area...and also led to muggy nights where the
temperatures remained in the 70s. Dewpoints during the meteorological
summer flirted with record values...and had it not been for the most
recent late august intrusion of drier air...the summer may have
broken records for the highest average dewpoint in recorded history.
Dewpoint is a measure of moisture in the air that is often compared
to relative humidity. Relative humidity is the amount of moisture
relative /hence the name/ to the air temperature. High relative
humidities happen year-round...but we seldom feel uncomfortable in
high humidity except for the summertime. A 60 percent humidity on a
40 degree day means little to us. However...a 60 percent humidity on
a 90 degree day means heat advisories are issued and conditions can
become dangerous. so instead of humidity...the dewpoint becomes the
focus for summertime discomfort as a better and more accurate
representation of moisture in the air.
At the three large metro areas in the NWS Wilmington forecast
area...near record dewpoints were seen this summer.
CINCINNATI AREA
---------------
Hourly dewpoint observations in the Cincinnati metro area were
analyzed back to 1930...a period of 80 years. For the period from
1930 to 1947...observations from Lunken field /LUK/ were used...and
from 1948 through August 31 2010...observations from the greater
Cincinnati airport /CVG/ were used. Below is a table of the highest
average hourly dewpoint for the summer season...and the highest
individual hourly dewpoint measured during that respective summer
for the Cincinnati metro area since 1930.
YEAR AVERAGE DEWPOINT MAX HOURLY DEWPOINT MEASURED
----------------------------------------------------------------
1995 66.6 79
1943 66.3 82
2010** 65.9 77
1977 65.7 78
1998 65.5 78
1980 65.3 78
1942 65.3 77
1935 65.0 79
1949 65.0 77
1937 65.0 79
The highest observed dewpoint ever measured in the available records
is 82 degrees at 5 pm on July 17th 1943. Dewpoints of 80 degrees or
more have only been measured 11 times in the past 80 years in
Cincinnati...most recently on June 19th 1975 at 6 pm.
Not only were the dewpoints high this summer...but warm temperatures
made for one of the warmer summers in Cincinnati history. According
to records dating back to 1872 in the Cincinnati area...the summer
of 2010 will go down as the 12th warmest summer ever recorded. Below
is a table of the 15 warmest meteorological summers in the
Cincinnati area. it could be argued that summer 2010 was the most
uncomfortable ever in terms of combined heat/humidity...with only
the summer of 1943 showing similar combinations of high heat and
humidity.
YEAR AVERAGE SUMMER TEMPERATURE
------------------------------------------
1934 78.8
1936 78.7
1874 78.6
1881 78.4
1901 78.0
1913 77.6
1872 77.6
1876 77.5
1914 77.4
1873 77.3
1944 77.2
2010 77.0**
1898 77.0
2007 76.8
1943 76.8
COLUMBUS AREA
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Hourly dewpoint observations in the Columbus metro area were
analyzed back to 1930...a period of 80 years. Below is a table of
the highest average hourly dewpoint for the summer season...and the
highest individual hourly dewpoint measured during that respective
summer for the Columbus metro area since 1930.
YEAR AVERAGE DEWPOINT MAX HOURLY DEWPOINT MEASURED
----------------------------------------------------------------
1995 66.0 80
1975 65.7 77
1949 64.7 77
1987 64.4 77
2010 63.8 78
1943 63.8 77
1947 63.7 77
2002 63.3 75
1980 63.3 80
1993 63.3 79
The highest observed dewpoint ever measured in the available records
is 80 degrees which occurred three different times...most recently
at 9 pm on July 27th 1997. Dewpoints of 80 degrees or more have only
been measured 4 times in the past 80 years in Columbus.
Not only were the dewpoints high this summer...but warm temperatures
made for one of the warmer summers in Columbus. According to records
dating back to 1879 in the Columbus area...the summer of 2010 will
go down as tied for the 5th warmest summer ever recorded. Below is a
table of the 10 warmest meteorological summers in the Columbus area.
It could be argued that summer 2010 was the most uncomfortable in
the last 80 years in terms of combined heat/humidity...with only the
summers of 1995...2002 and 1949 showing similar combinations of high
heat and humidity.
YEAR AVERAGE SUMMER TEMPERATURE
------------------------------------------
1934 77.1
1936 76.6
1901 76.0
2005 76.0
1999 75.9
2002 75.9
2010 75.9
1995 75.8
1991 75.8
1949 75.6
DAYTON AREA
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Hourly dewpoint observations in the Dayton metro area were analyzed
back to 1937...a period of 73 years. Below is a table of the highest
average hourly dewpoint for the summer season...and the highest
individual hourly dewpoint measured during that respective summer
for the Dayton metro area since 1937.
YEAR AVERAGE DEWPOINT MAX HOURLY DEWPOINT MEASURED
----------------------------------------------------------------
1995 65.5 78
1973 63.6 75
1949 63.6 77
1981 63.5 78
2010 63.4 78
1993 63.4 76
1980 63.1 80
1989 62.9 76
1987 62.9 77
1975 62.7 75
The highest observed dewpoint ever measured in the available records
is 80 degrees which occurred 18 different times...most recently at 1
pm on July 30th 1999.
Not only were the dewpoints high this summer...but warm temperatures
made for one of the warmer summers in Dayton. According to records
dating back to 1878 in the Dayton area...the summer of 2010 will go
down as tied for the 12th warmest summer ever recorded. Below is a
table of the 15 warmest meteorological summers in the Dayton area.
It could be argued that summer 2010 was the most uncomfortable in
the last 73 years in terms of combined heat/humidity...with only the
summer of 1995 showing similar combinations of high heat and humidity.
YEAR AVERAGE SUMMER TEMPERATURE
------------------------------------------
1934 77.9
1936 77.7
1901 76.8
1921 76.0
1900 76.0
1988 75.6
1995 75.6
1954 75.5
1944 75.5
1931 75.5
1933 75.4
1952 75.2
2002 75.2
2010 75.2
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