June – Warmer and Wetter in Illinois, More to Follow

Summary: The statewide average temperature for June so far is 75.3 degrees, 4.4 degrees above normal. The statewide average precipitation for June is 3.61 inches, which is about 130% above normal. However, the precipitation is spread unevenly throughout the state. Above-normal temperatures are expected to continue for July.

Temperature: Both the average high and average low for June has been above normal (maps below). The average high ranged from the low 90s around St. Louis to the upper 80s in the southern two-thirds of Illinois. The average high ranged from the upper 70s to the low 80s in the northern third of the state. The average lows ranged from the upper 50s in northeast Illinois to the 60s for the rest of the state.

Precipitation: Precipitation was highly variable across Illinois, which is fairly typical for summer months (below). There are a few areas in pink with 10 to 15 inches. Areas in shades of orange and red have precipitation amounts of 4 to 10 inches, well above normal. The largest monthly total so far is Beecher City (Effingham County) with 11.22 inches. Meanwhile, rainfall has been less plentiful in western and southern Illinois with amounts of 2 inches or less.

Warmest May on Record for Illinois

Temperatures: Based on preliminary data, the statewide average temperature for May in Illinois was 70.6 degrees, 7.9 degrees above normal and the warmest May on record. The old record was 69.4 degrees set back in 1962. A brief examination of daily records indicates that Springfield, Champaign, Quincy, and Carbondale all had daily mean temperatures at or above normal for each day of the month. On the other hand, Chicago, Rockford, and Peoria had a few dips into the below-normal territory but overall finished above-normal for the month. Here is the graph of daily mean temperature departures from normal for Champaign-Urbana.