May Finished both Wetter and Warmer

For Illinois, the preliminary statewide average temperature was 64.1 degrees, 1.3 degrees above normal. Basically the first 17 days of the month ran on the cool side (1.4 degrees below normal) while the rest of the month ran on the warm side (4.8 degrees above normal). The map below shows the temperature departures.
The statewide average rainfall was 5.68 inches, 1.42 inches above normal or 133% of normal. The heaviest amounts for the month were in western Illinois between Quincy and the Quad Cities. Dallas City, along the Mississippi River, reported 9.07 inches for the month.

May 2010 temperature departure
Temperature Departure for May 2010 for the Midwest (click to enlarge).

Rainfall for the Midwest.
Rainfall totals for May 2010 for the Midwest (click to enlarge).

Warmest April on Record for Illinois

Based on preliminary data, the statewide average temperature for Illinois in April was 58.4 degrees, 6.2 degrees above normal and the warmest April on record. This beats the old record of 58.2 degrees set in 1955. Official statewide average temperature records go back to 1895. The warm temperatures in April were not unique to Illinois – the entire Midwest was much above normal (see map below).
April rainfall was 3.5 inches, just 0.3 inches below normal. Areas in western Illinois around received the most precipitation, over 5 inches in some locations. A CoCoRaHS observer in Matherville (Mercer County) reported 6.50 inches for the month.

April temperature departures
Temperature departures for April across the Midwest (click to enlarge).

Midwest precipitation for April
Precipitation totals for April across the Midwest (click to enlarge).

March Was Warmer and Drier than Normal

Champaign, Ill. – Based on preliminary data in Illinois, the statewide average temperature for March was 43.6 degrees, 2.5 degrees above normal. This ends a three-month streak of colder than normal temperatures that occurred this winter, according to State Climatologist Jim Angel of the Illinois State Water Survey (http://www.isws.illinois.edu).
The statewide average precipitation was 2.8 inches, 0.4 inches below normal. A year ago, the March precipitation was 4.2 inches, an inch above normal, signaling the start of a very wet growing season.
This year, the January to March precipitation total was 5.8 inches, 1.4 inches below normal. Drier conditions this year have helped soil moisture return to conditions more typical for this time of year after an exceptionally wet fall.
The latest National Weather Service outlook for April calls for an increased chance of above normal temperatures across Illinois and the Corn Belt. An increased chance of above normal precipitation is indicated for the western Corn Belt, including western Illinois. The eastern half of Illinois has an equal chance of above, below, and near normal precipitation.
“March certainly came in like a lion and out like a lamb. The average statewide temperature on March 1 was 32 degrees but warmed up to 58 degrees on March 31,” concludes Angel.