August 2009 and Summer 2009 Saint Cloud Weather Summary

Cool Enough to Brag About

9th Coolest Summer in St. Cloud Records

Saint Cloud Weather Summary for August 2009 and Summer 2009

Issued: Wednesday, September 2, 2009 7:00 AM

The frustration with 2009's perpetual May temperatures was borne out by the weather statistics. The final summer (June 1-August 31) average temperature at the Saint Cloud Regional Airport was 65.1°F, 2.3°F colder than normal. This tied 1884 as the ninth coolest St. Cloud summer since temperatures began in 1881. Still, it wasn't quite as cool as 2004, which was nearly another degree cooler and ranks as the fourth coolest summer.

There were only two days with a high of at least 90°F (average number: 12 for the warm season), none of them in August and only one of them during the summer months. In the last 47 years since 1962, only 1981 and 1993 have had two or fewer days that warm. One of those warm days was May 20, when the high was a record 92°F. Of the 103 days that followed, only 26 days had an above normal temperature with only 3 July days having an above normal temperature. The cool weather produced two record cold highs temperatures in June and 5 record cool temperatures in July. July was also the third coolest July in St. Cloud records.

The cool weather left most agricultural stations short on growing degree days (total of average temperatures above 50 degrees) by 10-20% in central and southern Minnesota and by 25-40% in northern Minnesota, according to the August 31 Minnesota precipitation and temperature summary from the State Climatology Office. This has caused both the soybean and crop crops to be maturing more slowly than normal, according to this week's Minnesota Ag News from the US Dept. of Agriculture. This means that we will need a later than normal frost and freeze to allow the crops to finish maturing.

August 2009 actually was the closest to normal temperatures of any summer month. The average Saint Cloud temperature was 65.9°F, 1.3°F colder than normal.

The persistent dry growing season eased a bit in August. The August Saint Cloud Regional Airport rainfall was 5.23 inches, 1.30 inches above normal. Most of this rainfall took place between August 7 and August 21, during which 4.75 inches of rain fell at the St. Cloud Airport. Before that day, St. Cloud had picked up 9.29 inches during the growing season (April 1-August 6) was more than four and a quarter inches behind in growing season rainfall. So, those two weeks increased the rainfall by 50%. The St. Cloud Airport's heaviest rainfall was on August 7-8 when 2.35 inches fell. The 2.14 inches on August 8 set a daily record for rainfall.

However, most of the rainfall occurred in outbreaks of heavy, and sometimes severe, thunderstorms. That means that rainfall varied widely throughout the area. On August 7-8, southeastern Stearns County picked up over 3 inches (3.88 inches at SCSU, the fourth heaviest 24-hr rainfall event of the past 18 years), and a strip from Clara City to the southwestern Twin Cities suburbs got 3-6 inches. Chaska had 6.20 inches. There was also an EF-1 tornado along the west and northern shores of Lake Minnetonka. Another heavy rain storm dumped 3-6 inches to our east in the St. Croix Valley on August 19, but also produced 11 tornadoes in Minnesota and Wisconsin, including a couple of small, brief tornadoes in south Minneapolis and Cottage Grove.

These heavy rainfalls didn't complete end the dry conditions seen over Minnesota and Wisconsin, as seen on the US Drought Monitor. However, it did ease the area of extreme drought seen from the Twin Cities Metro through northwestern Wisconsin (see 12-Week Loop of US Drought Monitor). As of the end of the month, the Minnesota State Climatology Office's drought summary shows several areas with rainfall deficits of 5-8 inches, most notably in the Lake Minnewaska area and patches of 4-6 inch deficits in north central Minnesota, the Minnesota River valley, and parts of the St. Croix Valley. On the other hand, the repeated high rainfall amounts in eastern Stearns County (for comparison, SCSU got 8.57 inches of rain in August) makes this area about the only one in the state with near normal rainfall for the growing season.

Despite the dry spots, only 19% of the state has topsoil ranked as being short or very short, according to the weekly Minnesota Ag Newsletter from the USDA.

Ironically, after all of this cool weather, September is actually beginning with a prolonged period of normal to above normal temperatures. The dry weather, however, will continue into at least early next week.

    August 2009 Statistics

Summer (June 1-August 31) 2009 Statistics