Cold, Wet and Gloomy October 2009

A Treat at the End of October: Double Rainbow Over the Duluth Shipping Canal

A Treat at the End of October: Double Rainbow Over the Duluth Shipping Canal
Courtesy: Lake Superior Marine Museum Association

There was more trick than treat regarding the weather this October in the Twin Cities. Through 7am, October 31, October 2009 was the fifth wettest October on record (1891-2009) with 5.57 inches. This includes the 2.8 inches of snow that fell during the month, making October 2009 the seventh snowiest October in the Twin Cities and the most snow since 1991. It was a cold month as well. Factoring in estimated high and low temperatures for October 31, October 2009 will be the 4th coldest on record with 43.2 degrees. The coldest October on record is a bone-chilling 38.2 degrees set back in 1925.

Along with the wet and cold, came gloomy skies. Based on solar radiation records measured at the St. Paul Campus Climate Observatory since 1963, this was the gloomiest October since records began 47 years ago. There was measurable precipitation on 16 days of the month in the Twin Cities, a three-way tie with 1941 and 1982 for the most days with measurable precipitation in October (assuming it will stay dry this Halloween). In October on average there is measurable precipitation on eight days of the month.

Including the brief moment the mercury hit 60 on October 30 in the Twin Cities, the maximum temperature reached 60 degrees or higher only three times in October 2009. The only other years to have so few 60 degrees or higher readings in October were 1925 with two days and 1917 with three days. Having a lack of 60 degree readings in October does not seem to have a bearing on the number of times the high temperature reaches 60 in November. In fact in 1917, the high temperature reached 60 or above in November five times.

The thermometer did not reach 70 in October 2009. This has only happened three other times since 1891. Those years were 1917, 1925 and 1981. The highest temperature for the month was 64 degrees. The only year that had a colder maximum temperature for the whole month was 1925 with a high of only 60 degrees for the month.

Top ten precipitation amounts for October in the Twin Cities.

Rank  total Precip      Year
1       6.42            1911
2       5.68            1971
3       5.64            1934
4       5.62            1968
5       5.57            2009
6       5.52            1941
7       5.51            1898
8       5.48            1984
9       5.45            2005
10      4.97            1970

Top ten coolest average temperatures for October in the Twin Cities.

Rank  Avg temperature   Year
1       38.2            1925
2       38.6            1917
3       41.8            2002
4       43.2            2009
5       43.7            1972
6       44.0            1988
7       44.4            1952
        44.4            1959 (tie)
9       44.6            1976
        44.6            1987 (tie)

The cold and wet conditions were not confined to the Twin Cities. In other places around the state, Duluth will finish with its 9th coldest October. St. Cloud will have its 3rd wettest October and Rochester will have its 2nd wettest October. The 7.9 inches of snow that fell for the month in Rochester was the most snow recorded for Rochester since 1893. October rainfall totals were in excess of five inches in many locales in the southern two-thirds of the state, topping the historical October average by more than three inches. In some communities, it was the wettest October in the modern record.