August, summer weather was cool; dry in Illinois
Grundy wetter in August, drier over summer than state
CHAMPAIGN – While Grundy County measured more than three inches of rain last month, the statewide average precipitation for August was just 1.38 inches.
According to state climatologist Jim Angel of the Illinois State Water Survey, Prairie Research Institute, at the University of Illinois, the low rainfall total made it the third driest August on record. The statewide average was 2.22 inches below the 1981 to 2010 average for the eighth month of the year.
The driest August in Illinois was in 1952, with only 1.12 inches of rain. Even though last year was remembered for the severe drought, the August 2012 precipitation was 3.64 inches, which was 0.04 inches above average.
The only areas with significant precipitation this August were far southern Illinois and a portion of northeastern Illinois. Elsewhere, precipitation amounts were far below average. A few areas in western Illinois received less than 0.1 inches.
Nevertheless, according to the Weather Data Division of the Grundy County Emergency Management Agency, rainfall at Morris measured 3.29 inches during August.
The county nearly matched the statewide average for the month in one day, with 1.24 inches of rain falling in the 24 hours preceding 8 a.m. Aug. 3. Measurable rain fell on six days during the month.
The statewide average temperature for August was 73.1 degrees F, which is only 0.4 degrees below average. August was noteworthy for being much below average for the first half of the month and much above average for the latter half, effectively canceling each other out by the end of the month.
According to the Grundy EMA, the Morris average temperature locally for the month was 73 degrees.
A similar divide in temperatures between early and late August was evident from the high and low mercury marks for the month. The high for the month was 94 degrees Aug. 30, while the low was 72 degrees recorded Aug. 5.
There were just two days during August when the temperature hit 90 degrees or higher.
The statewide average precipitation for summer (June, July and August) was 9.93 inches, which is 1.92 inches below average. While June was above average (5.41 inches), both July (3.14 inches) and August (1.38 inches) were below average.
It was an improvement over last summer when the average precipitation for the summer was 6.92 inches, 4.93 inches below the 1981 to 2010 average.
The statewide average temperature for this summer was 72.5 degrees, 1.1 degrees below the 1981 to 2010 average. June, July and August were all below average, but July had the coolest departure of 2.4 degrees below average.
The statewide average precipitation for 2013 so far was 33.48 inches, which was 6.0 inches above the 1981 to 2010 average. This was far higher than last year, when the statewide precipitation was only 17.79 inches through the end of August – an amount almost half of this year’s precipitation.
Precipitation in Grundy County is trailing behind the statewide average through the first three meteorological seasons, with August rainfall bringing the precipitation total for the year to 30.35 inches locally.
The statewide average temperature for 2013 so far was 46.3 degrees, which was 1.2 degrees below the 1981 to 2010 average. This was far cooler than last year when the statewide temperature was 52.7 degrees, 5.2 degrees above average.
The Illinois State Water Survey at the University of Illinois at Urbana-Champaign, a division of the Prairie Research Institute, is the primary agency in Illinois concerned with water and atmospheric resources.