February 2022 Overview
Temperatures were below and precipitation was above the long-term average in Illinois in February. Aggregate statistics of mean streamflow statewide were not available. Shallow groundwater levels were above the long-term depths.
Air temperatures averaged 28.0 degrees F, 1.2 degrees below the 1991–2020 normal for February (Figure 1). February average temperatures ranged from the low 20s in northern and north-central Illinois to the high 30s in far southern Illinois, between 1 and 6 degrees below the 1991–2020 normal.
Precipitation statewide in February was 3.10 inches, 1.24 inches above the long-term statewide average (Figure 1). Total February precipitation ranged from less than 1 inch in far northwest Illinois to over 9 inches in parts of southern Illinois.
Mean provisional streamflow was estimated to be mostly in the normal to much above normal range for February. Aggregate statistics of mean provisional flow statewide were not available for February 2022 because of frozen conditions at many streamgage stations.
Water surface levels at the end of February were below the full pool or target level at 2 of 25 reporting reservoirs. At the end of February, Lake Shelbyville was 8.8 feet above the winter target level, the Carlyle Lake level was 6.0 feet above the winter target level, and Rend Lake was 5.3 feet above the spillway level. Lake Michigan’s mean level was above its long-term mean for the month.
Shallow groundwater levels statewide were 0.46 feet above the long-term average at the end of February. Levels averaged 1.66 feet above those in January and 0.34 feet below those of last year.
Weather/Climate Information
The following description of temperatures, precipitation, severe weather, 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.
February in Illinois was cooler and wetter than average statewide.
Temperatures averaged 28.0 degrees F, 1.2 degrees below the 1991–2020 normal for February (Table 1a). February average temperatures ranged from the low 20s in northern and north-central Illinois to the high 30s in far southern Illinois, between 1 and 6 degrees below the 1991–2020 normal. Several stations saw daily high temperatures in the high 60s in mid-February, including 67 degrees in Alexander and Pope Counties. Meanwhile, stations in northern and central Illinois saw nighttime low temperatures well below 0, including -9 degrees in Knox County and -8 degrees in Woodford County.
Altogether, daily high maximum temperature records were broken at seven stations in February, and daily high minimum temperature records were broken at five stations. Despite the persistently below normal temperatures last month, no daily low minimum or low maximum temperature records were broken.
Figure 2. February 2022 Temperatures and Departures from Normal
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Precipitation statewide in February was 3.10 inches, 1.24 inches above the long-term statewide average (Table 1a). Total February precipitation ranged from less than 1 inch in far northwest Illinois to over 9 inches in parts of southern Illinois. Last month was about 1 inch drier than normal in northwest Illinois, 1 to 2 inches wetter than normal in central Illinois, and 4 to 7 inches wetter than normal in southern Illinois. Two observers near Cobden in Union County measured more than 9 inches of rain in February, one of the top 20 highest February totals on record statewide. Meanwhile, several stations in northwest Illinois recorded less than three-quarters of an inch of precipitation for February, including 0.63 inches in Freeport and 0.57 inches in Stockton. It was a top 10 driest February on record in Dubuque, Iowa.
Snow: After a very slow start to winter, much of the state finally saw considerable snowfall in February. A series of winter storms in early to mid-February brought several rounds of moderate to heavy snowfall, with the highest totals along and around the Interstate 55 corridor from St. Louis to Chicago.
Overall, February total snowfall ranged from less than 4 inches in southern and far northwest Illinois to over 20 inches in parts of central and northeast Illinois. February snowfall was 2 to 4 inches below normal in drought-stricken northwest Illinois, within 2 inches of normal in northeast and southern Illinois, and 6 to 12 inches above normal from the St. Louis Metro East through central Illinois into the southern Chicagoland area.
Drought: Unfortunately, February precipitation patterns reinforced a dry north-to-wet south pattern in Illinois, present since the fall. The heavy February rain and snow melt in southern Illinois has caused several spots along the Wabash and Ohio Rivers and tributaries to reach or exceed moderate flood stage. Excessively wet soils in southern Illinois also raise concerns of continued flooding risks and possible fieldwork issues as we approach the start of the growing season. Concurrently, the dry winter has not helped alleviate drought conditions across northern Illinois, as the U.S. Drought Monitor expanded or continued the moderate to severe drought designations from Lake County to Rock Island County.
Table 1a. February 2022 Temperature and Precipitation Summaries
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Table 1b. Winter 2021-22 Temperature and Precipitation Summaries
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Winter (December–February) was overall warmer than normal across Illinois. Seasonal temperatures averaged 30.1 degrees F, 2.1 degrees above the 1991–2020 normal (Table 1b), ranging from the low 20s in northern Illinois to the high 30s in southern Illinois.
Winter precipitation averaged 6.75 inches statewide, 0.44 inches above average (Table 1b). Climatological winter total precipitation ranged from just around 3 inches in far northwest Illinois to nearly 20 inches in southern Illinois. Winter was between 2 and 3 inches drier than normal in western and northwest Illinois, within 1 inch of normal in central Illinois, and 5 to 7 inches wetter than normal in far southern Illinois.
Illinois Climate Network (ICN) (Jennie Atkins)
The Illinois Climate Network (ICN) collects hourly weather and soil information from 19 stations across the state.
Wind speeds increased slightly from in January to a network average of 8.4 mph, 0.3 mph higher than in January and 0.1 mph higher than the long-term average. ICN Bondville (Champaign County) was again the windiest station with the highest monthly average of 13.1 mph and the highest recorded wind gust of 42.9 mph on February 22.
Air temperatures rose 5 degrees F from in January to an average of 29 degrees, 3 degrees cooler than the long-term average. Overall, the state saw both extremes during the month. Station highs were in the 50s and 60s, 16 to 22 degrees warmer than average. Lows ranged from -10 to 10 degrees, 18 to 32 degrees cooler than average. The lowest temperature, -10 degrees recorded at ICN Snicarte (Mason County) on February 5, was 76 degrees lower than the highest, 66 degrees recorded at ICN Dixon Springs (Pope County) on February 16.
Soil temperatures averaged in the mid-30s for the month, a difference of 1 to 2 degrees F from in January and 1 to 2 degrees cooler than the long-term averages. However, the minimum monthly temperatures at the 2- and 4-inch depths rose 4 to 8 degrees as central and southern Illinois received more snow than last month, insulating the soils to colder temperatures. Under bare soil, temperatures ranged from 28 to 60 degrees at 2 inches and from 24 to 55 degrees at 4 inches. Temperatures under sod ranged from 24 to 49 degrees at 4 inches and from 24 to 53 degrees at 8 inches.
Precipitation increased at most stations in February. The network averaged 3.68 inches for the month, 2.30 inches more than in January and 1.75 inches more than the long-term average. Southern Illinois was especially wet as five stations received more than 5 inches of precipitation. ICN Dixon Springs (Pope County) recorded 8.29 inches, the highest of the month, bringing its 2022 total to 13.01 inches.
ICN Freeport (Stephenson County), however, only received 0.60 inches of precipitation, the month’s lowest. Its 2022 total is 1.30 inches, 10 percent of which was at ICN Dixon Springs.
Soil moisture data will return to the IWCS in Spring 2022.
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 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.)
Aggregate statistics of monthly mean provisional streamflow statewide were not available for February 2022 because of frozen conditions at many streamgage stations. The limited amount of data posted suggests that monthly mean streamflow conditions ranged from normal to much above normal for February.
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 the 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 the 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-January water levels at 23 reservoirs for which levels were reported last month and this month, reported end-of-February water levels were lower at 2 reservoirs, higher at 15 reservoirs, and about the same as at the end of January at 6 reservoirs. For the 25 reservoirs with measurements reported at the end of February, water levels were below the normal target pool or spillway level at 2 reservoirs, above the normal target pool or spillway level at 15 reservoirs, and at about the full pool level at 8 reservoirs.
Major Reservoirs. Compared to water levels at the end of January, at the end of February the water level at Lake Shelbyville was 7.5 feet higher, Carlyle Lake was 5.8 feet higher, and Rend Lake was 3.4 feet higher. At the end of February, Lake Shelbyville was 8.8 feet above the winter target level, the Carlyle Lake level was 6.0 feet above the winter target level, and Rend Lake was 5.3 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 February 2022 mean level for Lake Michigan was 579.2 feet. The monthly mean level one year ago (February 2021) was 580.7 feet. The long-term average lake level for February is 578.4 feet, based on 1918–2021 data. In this period of record, the lowest mean level for Lake Michigan for February occurred in 1964 at 576.1 feet, and the highest mean level for February occurred in 2020 at 581.5 feet. The month-end level of Lake Michigan was 579.2 feet. All values are provided by the U.S. Army Corps of Engineers Detroit District.
Groundwater Information (Jennie Atkins)
Water tables rose throughout most of Illinois in February. Wet weather in most regions led to increases of up to 5.07 feet, as seen at the Sparta well in Randolph County. However, the Freeport well in northwest Stephenson County continued to decline, measuring 0.48 feet lower than last month. Overall, wells averaged 1.66 feet above January levels.
Statewide water levels averaged 0.34 feet below 2021 levels, 0.11 feet above the 15-year average, and 0.46 feet below the period of record. Dry conditions in the north continued to impact water tables. Besides a decline from in January, the Freeport well was 4.18 feet lower than in February 2021, 5.63 feet lower than the 15-year average, and 5.38 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
