In a climatological rarity, April was cooler than March for the official climate sites in Central Illinois. Lincoln, Peoria, and Springfield all recorded cooler mean temperatures in April than March. In a typical year, April's mean temperature is around 12 degrees warmer than March's mean temperature. However, this was not the case in 2012, as temperatures ran around 1 degree cooler in April than March. A review of the climate record shows this is a very rare occurrence. With records dating back to 1883 for Peoria, a cooler April occurred only in 1907. At Springfield, dating back to 1880, this occurred only in 1907 and 1918. This is the first such event in Lincoln, with records going back to 1909.
This unusual climate event was not the result of a cool April. In fact April temperatures were 2-3 degrees above normal. However, April was "cool" when compared to March which saw all-time record breaking warmth of 14-15 degrees above normal.
March & April 2012 Mean Temperature (and departure from normal)
|Peoria||55.4 (+14.8)||54.6 (+2.3)|
|Springfield||57.3 (+15.2)||56.8 (+3.5)|
Previous years with April cooler than March
April's rainfall was generally below normal for much of central and southeast Illinois. However, an active period of thunderstorm activity April 28-30th pushed monthly totals above normal for parts of west central and southwest Illinois. While April can be an active severe weather month in this part of the Midwest, only a few isolated high wind and hail events occurred this month.
Rainfall deficits for the past few months have led to abnormally dry conditions for much of central Illinois. The U.S. Drought Monitor below highlighs areas suffering the highest rainfall defecits as of late April.
Preliminary climate summaries for April 2012 are listed below. Only the summaries for Peoria, Springfield, and Lincoln are considered to be official climatological summaries. The remaining 4 sites are "supplemental", meaning another station in the area is the official climatological station for that location.