June 2022 Overview
June temperatures were above and precipitation was below the long-term average in Illinois. Mean streamflow statewide was below the median for the month. Shallow groundwater levels were below the long-term depths.
Air temperatures averaged 73.4 degrees F, 1.2 degrees above the 1991–2020 normal for June (Figure 1). Average temperatures ranged from the high 60s in far northern Illinois to the high 70s in southern Illinois, between 1 and 3 degrees above normal.
Precipitation statewide in June was 2.73 inches, 1.92 inches below the long-term statewide average (Figure 1). June total precipitation ranged from less than 1 inch in east-central Illinois to more than 5 inches in northwest Illinois.
Soil moisture levels declined at depths from 2 to 20 inches in June. At 2 inches, levels fell 35 percent in June to a state average of 0.19 water fraction by volume (wfv). The declines continued to 20 inches where soil moisture fell 16 percent. Moisture levels remained high at 3 and 5 feet, showing little change over the month.
Mean provisional streamflow aggregated statewide was below the long-term median flow for June, about 80 percent of the median (Figure 1). Monthly mean discharge values in June were mostly below normal to normal.
Water surface levels at the end of June were below the full pool or target level at 9 of 20 reporting reservoirs. At the end of June, Lake Shelbyville was 0.2 feet above the summer target level, Carlyle Lake’s level was 0.2 feet above the summer target level, and Rend Lake was 2.2 feet above the spillway level. Lake Michigan’s mean level was above its long-term mean for the month.
Shallow groundwater levels were 1.14 feet below the long-term average at the end of June (Figure 1). Levels averaged 1.19 feet below those in May and 0.93 below last year’s levels.
The following description of temperatures, precipitation, and drought comes from data compiled by networks that report to the National Oceanic and Atmospheric Administration (NOAA). These data are provisional and may change slightly over time.
June in Illinois was much warmer and drier than normal statewide.
Temperatures averaged 73.4 degrees F, 1.2 degrees above the 1991–2020 normal for June, tying for the 30th warmest June on record (Table 1). June average temperatures ranged from the high 60s in far northern Illinois to the high 70s in southern Illinois, between 1 and 3 degrees above normal (Figure 2). The warmest point in the state last month was Bean Ridge in Alexander County with an average June temperature of 78 degrees, and the coolest part of the state was Waukegan with an average June temperature of 67.7 degrees. The high temperatures and humidity in mid-June made for some very warm nights.
Altogether, daily high maximum temperature records were broken last month at 58 stations, and daily high minimum temperature records were broken at 97 stations. Eight stations broke their all-time June high nighttime temperature records, including a 78-degree low temperature in Peoria and an incredible 83-degree low at Chicago’s Midway Airport. The latter broke the previous June low temperature record at Midway by 4 degrees. Daily low minimum temperature records were broken at four stations, including a 46-degree low in Normal on June 19.
Precipitation statewide in June was 2.73 inches, 1.92 inches below the long-term statewide average and the 22nd driest June on record (Table 1). June total precipitation ranged from less than 1 inch in east-central Illinois to more than 5 inches in northwest Illinois (Figure 3). Only the Quad Cities area was wetter than normal in June, while other places in the state were between 0.5 inches and 3 inches drier than normal.
The wettest point in the state in June was Jacksonville, with just under 8 inches of rain. In contrast, Sidell in Vermilion County received just 0.60 inches in June. Last month was the fourth driest June on record in Champaign-Urbana, the fifth driest on record in Carbondale, the sixth driest on record in Belleville, and the seventh driest on record in Danville.
Drought: The very dry June weather in east-central Illinois followed a subtly dry May, resulting in precipitation deficits of between 4 and 8 inches since the start of the growing season in all or parts of Piatt, Champaign, Vermilion, and Douglas Counties. Meanwhile, parts of southern and northeast Illinois also dried out in June, and soil moisture was quickly depleted from the combination of a lack of rainfall and very high evaporation rates. In response, the latest version of the U.S. Drought Monitor shows moderate drought stretching from DeKalb County to Clark County and spilling over the Indiana and Kentucky borders from White to Alexander Counties.
The driest part of the state in east-central Illinois is currently in severe drought, as persistent stress has lawns dormant and corn and soybeans visibly stressed across the area.
Illinois Climate Network (ICN) (Jennie Atkins)
The Illinois Climate Network (ICN) collects hourly weather and soil information from 19 stations across the state.
Winds speeds decreased in June to an average of 5.3 mph, 0.6 mph lower than the long-term average and 2.4 mph lower than in May. ICN Monmouth (Warren County) had the highest monthly average at 8.6 mph. The highest recorded wind gust was 54.8 mph, measured at ICN Brownstown (Fayette County) on June 17.
Temperatures averaged 74 degrees F in June, 8 degrees higher than in May and 2 degrees above the long-term average. Station highs were mainly in the mid- to high 90s. ICN Brownstown (Fayette County) had the network’s highest temperature, recording 100 degrees on June 16.
Lows were in the 40s and 50s. The lowest temperature of the month was 46 degrees, measured at ICN Big Bend (Whiteside County) on June 19.
Soil temperatures rose 10–11 degrees from in May to averages in the mid- to high 70s, 3 degrees above the long-term averages. Under bare soil, temperatures ranged from 55 to 118 degrees at 2 inches and 57 to 111 degrees at 4 inches. Temperatures under sod ranged from 61 to 96 degrees at 4 inches and 62 to 89 degrees at 8 inches.
Precipitation averaged 2.66 inches across the network in June, 1.23 inches less than in May and 0.93 inches below the long-term average. The month was dry in eastern Illinois. ICN Champaign (Champaign County) recorded only 0.78 inches of precipitation in June, 21 percent of its long-term average.
However, ICN Perry (Pike County) received 5.45 inches, 139 percent of normal, and the month’s highest total.
The drier, hotter weather caused soils to continue to dry through June. Soil moisture at 2 inches fell 35 percent to an end-of-month average of 0.19 water fraction by volume (wfv). The largest drop was in northern Illinois with a decline of 41 percent, but all regions saw moisture levels fall by more than 30 percent. Soils ended the month at or near the wilting point in the north and east.
Drying extended to 20 inches where moisture levels fell 16 percent. However, soil moisture remained high at 3 and 5 feet, showing little change over the month.
Surface Water Information (Bill Saylor)
Provisional monthly mean flows for this month for 26 streamgaging stations located throughout Illinois are shown in Table 2, compared to statistics of the past record of monthly mean flows at those stations for the same month. Both recent and long-term data are retrieved from U.S. Geological Survey (USGS) online data services following the end of the month. Years of record values in Table 2 represent the number of past monthly values included in the Table 2 statistics; at some stations, the available record may not be continuous. Additional source data may be available from the USGS.
The statewide percent of historical mean flow and percent of historical median flow are calculated by dividing the sum of the average flows this month at stations in Table 2 by the sum of the historical mean and median flows calculated for the month, respectively, at the same stations. This method is intended to weight individual observations proportionately in the aggregate comparison. (The Illinois River and Rock River stations are excluded from the statewide calculation because other rivers listed in Table 2 contribute to their flow.)
Mean provisional flow aggregated statewide, using the available monthly mean data shown this month in Table 2, was below the median value for June (approximately 80 percent of the median) and below the mean for June (approximately 60 percent of the mean). Monthly mean discharge values in June were mostly below normal to normal, except for the La Moine River at Ripley and Bear Creek near Marceline in west-central Illinois, where monthly mean streamflows were above normal.
Water-Supply Lakes and Major Reservoirs. Table 3 lists selected reservoirs in Illinois, their normal pool or target water surface elevation, and data related to observed variations in water surface elevations. Reservoir levels are obtained from a network of cooperating reservoir operators who report water levels each month. Current reservoir levels reported in Table 3 are representative of the end of the reported month and are presented as the difference in feet from seasonal target level or from full pool, as applies. Years of record represent the number of past reports for the same month used to calculate the average of the month-end values presented in Table 3. For some reservoirs, this average does not include an additional period of record prior to a substantial change in reservoir operation. Most reservoirs in Table 3 serve as public water supplies, with the exceptions noted in the last column.
Compared to end-of-May water levels at 19 reservoirs for which levels were reported last month and this month, reported end-of-June water levels were lower at 13 reservoirs, higher at 3 reservoirs, and about the same as at the end of May at 3 reservoirs. For the 20 reservoirs with measurements reported at the end of June, water levels were below normal target pool or spillway level at 9 reservoirs, above normal target pool or spillway level at 9 reservoirs, and at about full pool level at 2 reservoirs. Inflow to Salem Lake in June was supplemented by pumping from Carlyle Lake.
In early June 2022, the City of Mt. Olive switched its water supply to purchase from the City of Litchfield water system. Water levels of the Mt. Olive lakes and system pumpage data will no longer be reported in the Illinois Water and Climate Summary. Also, Hillsboro Lake is deleted from Table 3, as the operator has confirmed its status as a backup supply source only for the City of Hillsboro. Pumpage reported for the Hillsboro system is from Lake Glenn Shoals and will be listed as such in Table 2.
Major Reservoirs. Compared to water levels at the end of May, at the end of June the water level at Lake Shelbyville was 0.5 feet lower, Carlyle Lake was 0.5 feet lower, and Rend Lake was 1.4 feet lower. At the end of June, Lake Shelbyville was 0.2 feet above the summer target level, Carlyle Lake’s level was 0.2 feet above the summer target level, and Rend Lake was 2.2 feet above the spillway level.
Great Lakes. Current month mean and end-of-month values are provisional and are relative to International Great Lakes Datum 1985. The June 2022 mean level for Lake Michigan was 580.1 feet. The monthly mean level one year ago (June 2021) was 580.6 feet. The long-term average lake level for June is 579.3 feet, based on 1918–2021 data. In this period of record, the lowest mean level for Lake Michigan for June occurred in 1964 at 576.6 feet, and the highest mean level for June occurred in 2020 at 582.2 feet. The month-end level of Lake Michigan was 580.1 feet. All values are provided by the U.S. Army Corps of Engineers Detroit District.
Groundwater Information (Jennie Atkins)
Drier weather led to continued declines at most WARM monitoring wells in June. Only one well, Mt. Morris (Ogle County), showed an increase from last month. Wells averaged 1.19 feet lower than in May with ranges from 3.09 feet below to 0.10 feet above.
Water table levels were also lower than last year’s, averaging 0.93 feet below those in June 2021 and ranging from 3.20 feet below to 2.12 feet above.
Levels averaged 1.60 feet below the 15-year average and 1.14 feet below the period of record.
Data sources for the IWCS include the following:
CPC - Climate Prediction Center, https://www.cpc.ncep.noaa.gov/index.php
ISWS - Illinois State Water Survey, https://www.isws.illinois.edu
MRCC - Midwestern Regional Climate Center, https://mrcc.purdue.edu/
NCEI - National Centers for Environmental Information, https://www.ncei.noaa.gov
NWS - National Weather Service, https://www.nws.noaa.gov
SPC - Storm Prediction Center, https://www.spc.noaa.gov
USACE - U.S. Army Corps of Engineers, https://www.lre.usace.army.mil
USDM - U.S. Drought Monitor, https://droughtmonitor.unl.edu
USGS - U.S. Geological Survey, https://waterdata.usgs.gov/il/nwis
WARM - Water and Atmospheric Resources Monitoring Program, https://www.isws.illinois.edu/warm