August 2008 will go down as a sunny but cooler and drier than normal month. The average temperature for August was 72.7 degrees which is 1.2 degrees below normal. The warmest day came early with a high of 95 degrees on the 3rd. A strong cold front swept through the state toward the middle of the month with a high temperature of only 70 degrees on the 12th. The coolest overnight low came on the 29th with a low of 56. No records were broken.
1.94 inches of rain fell during the month which is 2.57 inches below normal. 0.66 inches fell on the 14th, the most of any day, with only 7 days of measurable precipitation. August was the sunniest month on record with 91% sunshine. This smashed the old record of 86% set in 1983 and 1955. The 91% tied the second sunniest month of all time which was in July of 1916. The sunniest month was 94% back in July 1936.
For the summer season, which is defined as June 1 through August 31, no temperature extremes were noted. However rainfall for Des Moines was the 3rd wettest on record with 23.57 inches. 1993 was the wettest with 29.67 inches. For the year, Des Moines is 12.22 inches above normal or around 148% of normal.
The month ended up cooler and drier than normal at Waterloo. The average temperature was 69.9 degrees which is 1.3 degrees below normal. The warmest day was the 4th with a high of 89 degrees. The coolest temperatures were on the 25th and 26th when the overnight low dipped down to 49. No records were broken.
1.58 inches of precipitation fell during August which is 2.50 inches below normal. The greatest daily rainfall occurred on the 9th and 29th with 0.56 inches recorded on both of those days. There was only 8 days with measurable precipitation. So far this year Waterloo has received 37.86 inches of precipitation which is 13.36 inches above normal, or 155% of normal.