The preliminary statewide average June temperature was 72.0 degrees, 0.2 degrees below the 1991–2020 normal, 0.6 degrees above the 20th Century average, 0.3 degrees below the most recent 30-year average and tied for 61st warmest June on record.
The preliminary statewide total June precipitation was 7.40 inches, 2.75 inches above the 1991–2020 normal, 3.31 inches above the 20th Century average, 7.78 inches above the most recent 30-year average, and the 5th wettest June on record.
Data are provisional and may change slightly over time.
Summer Turned on in Late June
June began on the warm side with daily average temperatures that were 4 to 8 degrees above average statewide. A large cold front moved through around June 10th and beckoned a large trough that allowed cooler Canadian air to regularly sneak into the state in the middle and later parts of June. Daily average temperatures and departures from normal in Kewanee show the swing from warmer to cooler weather last month (Figure 1). A few days in mid-June were 10 to 15 degrees cooler than average in parts of northern and central Illinois.
Overall, June average temperatures ranged from the high 60s in northern Illinois to the mid-70s in southern Illinois. Most of the northern half of the state was near normal to 2 degrees cooler than normal, while much of southern Illinois was around 1 degree warmer than normal last month (Figure 2).
However, below average temperatures in mid-June brought a few sub-50-degree nighttime lows in central and northern Illinois, including 43 degrees in Danville and 45 in Rockford. Extreme heat in the last two days of June pushed daytime highs well into the 90s, including highs of 96 degrees in Alton and 94 in Chicago. The warmest place in the state last month was Morrisonville in Christian County with an average temperature of 76.9 degrees. The coolest place in the state last month was Waukegan with an average temperature of 66.8 degrees. Last month was the coolest June in Peoria since 2013.
Overall, the preliminary statewide average June temperature was 72.0 degrees, 0.2 degrees below the 1991–2020 normal, 0.6 degrees above the 20th Century average, 0.3 degrees below the most recent 30-year average and tied for 61st warmest June on record.
Very Rainy June
June is typically one of the wettest months of the year in Illinois. In some years, June precipitation is consistent across the state, often the case in the wettest of Junes. Last month followed that pattern with frequent, often heavy rain blessing or plaguing central and northern Illinois throughout the month. The same upper-level trough that brought us cooler weather mid-month also kept an active storm track in central Illinois, particularly, producing seriously high rainfall totals. Total June rainfall ranged from over 12 inches in parts of central Illinois to less than 2 inches in southern Illinois (Figure 3).
Last month was the 5th wettest June on record in Peoria and the 3rd wettest on record in Bloomington-Normal and Galesburg. The heavy rainfall caused widespread flooding on the Illinois, Mackinaw, and Vermilion Rivers among others in central Illinois last month. The Illinois River at Havana reached its highest stage (19.82 feet) since 2020. Meanwhile, the rain was harder to come by in southern Illinois, especially around the Carbondale-Marion area. Carbondale has amassed quite a precipitation deficit this year so far, with the driest first half of the year there since 2012.
The preliminary statewide total June precipitation was 7.40 inches, 2.75 inches above the 1991–2020 normal, 3.31 inches above the 20th Century average, 7.78 inches above the most recent 30-year average, and the 5th wettest June on record.
Severe Weather
June is one of our most active severe weather months; however, this month was next level. Last month saw multiple, very large tornado outbreaks across Illinois, producing at least 65 tornadoes. Among these were multiple large, EF-3 tornadoes in Effingham County and Jefferson County, and unfortunately related fatalities and injuries. The incredibly active severe weather month continued a record-breaking tornado year in Illinois. As of July 1st, our state had 173 tornadoes, smashing the previous annual record of 142 in 2024, and doubling the next most active state this year. Illinois has now had over 100 tornadoes four years in a row after only surpassing the century mark four times between 1950 and 2022 (Figure 4). To set a new tornado record yet again is remarkable, but to do so before the halfway point in the year is nothing short of extraordinary, but in a bad way.
Among the tornadoes, storms also produced dozens of hail damage reports and nearly 300 severe wind reports, including those from a derecho that affected the Chicagoland area in mid-June. last year.
Outlooks
July is the climatologically hottest month of the year in Illinois and can make or break a growing season with its rain (or lack thereof). The latest July outlooks from the Climate Prediction Center continue to show a whole lot of nothing, at least at first glance (Figure 5). Equal chances of warmer, cooler, drier, and wetter than normal weather may seem unhelpful. However, the lack of a warm signal in the Midwest may speak to good chances of moving back into a cooler and wetter pattern in early to mid July, before having some more heat come back in later in the month. It’s always worth noting that July precipitation often comes in the form of isolated thunderstorms that can produce large differences in totals over small distances.
We do start to see some signals in the outlooks for the three-month period between July and September (Figure 6). Notably, Illinois is completely covered by higher chances of some cooler than normal weather to wrap up summer and start fall, while precipitation remains equally divided between chances of drier and wetter weather.
