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Illinois was both cooler and drier than the 1991–2020 normal in 2022. The statewide average annual temperature was 52.0 degrees, 0.6 degrees below normal and tied for the 51^st warmest on record. Statewide average total precipitation in 2022 was 37.24 inches, 3.51 inches below normal and the 61^st driest year on record.

2022 Temperatures

Following the second warmest December on record statewide, temperatures moderated quite a bit to start 2022. January and February average temperatures were 4.5 degrees and 3.2 degrees below the 1991–2020 normals, respectively. Spring was a mixed bag, with a very warm March and May split by an April that was nearly 3 degrees colder than normal. A hot start to summer pushed June 1.3 degrees above normal statewide, while July was only 0.3 degrees warmer than normal and August’s average temperature equaled the normal. Fall was very pleasant, as September and November were both just slightly warmer than normal, while October was 1.3 degrees colder than normal statewide. A December full of wild temperature swings ended just over 1 degree colder than normal to cap off 2022.

Overall, the statewide average annual temperature was 52.0 degrees, 0.6 degrees below normal (Figure 1). However, because Illinois has experienced a 100+ year warming trend as part of human-caused climate change, the statewide average annual temperature was still 0.4 degrees above the 20^th century average, and 2022 tied for the 51^st warmest on record statewide.

Figure 2 shows 2022 average temperatures and departures from normal across the state. Average temperatures ranged from the low 40s in northern Illinois to the low 50s in southern Illinois. Most of the state was within 1 degree of the 30-year normal, while part of western Illinois was between 1 and 2 degrees colder than normal in 2022.

The year 2022 was the 34^th warmest on record in Chicago, 27^th warmest on record in St. Louis, 45^th warmest on record in Peoria, 50^th warmest on record in Rockford, and 48^th warmest on record in Moline. The year was also the 60^th coolest on record in Springfield, 52^nd coolest on record in Quincy, and 39^th coolest on record in Carbondale. Bean Ridge in Alexander County was the warmest point in the state in 2022 with an average temperature of 59.5 degrees. Elizabeth in Jo Daviess County was the coldest point in the state last year with an average temperature of 46.6 degrees.

Table 1 shows the number of daily weather records broken at Illinois Cooperative Observer stations in each month of 2022. May led with the highest number of high daily maximum and high daily minimum temperature records, with over 150 of each. Three stations in Illinois broke their all-time May high maximum temperature records in 2022, including a 96-degree high in Rock Island and a 99-degree high in Chenoa. Eleven stations also broke their all-time May high minimum temperature records in 2022, including an 80-degree low temperature in Rock Island and a 74-degree low in Peoria.

The heatwave that broke so many daily weather records across Illinois was remarkable in many ways. First, it occurred in the first half of May, while most May temperature records are set in the latter half of the month. The heat itself was extreme with most places in the state experiencing multiple days with high temperatures in the mid- to upper 90s. Lastly, the heat arrived very quickly and followed a prolonged period of cooler weather in April and early May. A rapid change from cool to hot weather, especially early in the warm season, is associated with an elevated risk of heat-related health impacts.

The Excess Heat Factor (EHF) is a metric used to account for the intensity of a heat wave and how well an area was acclimated (or not acclimated) to the heat ahead of the heat wave. Figure 3 shows all heat waves on record in Rockford, expressed as their EHF value, with higher values indicating more extreme heat waves. Because of its intensity in absolute temperature and compared to the prior cool period in April, the May 2022 heat wave had the highest EHF value of any heat wave on record in Rockford.

Milder temperatures in April, October, and November also resulted in dozens of low maximum and low minimum temperature records broken across the state in 2022. However, three times as many high maximum or high minimum temperature records (791) were broken last year in Illinois as low maximum or low minimum temperature records (247).

There were also 538 daily total precipitation records broken across Illinois in 2022. Daily precipitation records broken were somewhat equally spread among months, but July led with 90 records.

2022 Precipitation

Calendar year 2022 began with a very dry January, with less than 50 percent of normal precipitation statewide. February and March were 1.04 inches and 1.42 inches wetter than normal, respectively, making for wet soils heading into the spring. While April was slightly drier than normal statewide, many places in the state had a double-digit number of days with measurable rain. Macomb, for example, had 25 out of 30 April days with measurable rainfall, but was still drier than normal for the month. May was slightly drier than normal, and June was nearly 2 inches drier than normal statewide. Meanwhile, July and August were both wetter than normal, followed by all three fall months with below normal precipitation. December wrapped up 2022 just slightly drier than normal statewide (Figure 4).

Overall, statewide average total precipitation in 2022 was 37.24 inches, 3.51 inches below normal and the 61^st driest year on record.

Much like past years, the statewide preciptiation statistics are not representative of all places in Illinois. Calendar year 2022 was somewhat to much drier than normal in most of central and southern Illinois, but wetter than normal in areas that experienced extreme rainfall, such as the St. Louis Metro East and far northern Illinois. Last year was the 14^th driest on record in Mt Vernon, the 50^th driest on record in Champaign, and the 41^st driest on record in Moline; however, it was also the 30^th wettest on record in Edwardsville and the 9^th wettest on record in Freeport.

Figure 5 shows the spatial variability of 2022 precipitation in more detail. Total precipitation in 2022 ranged from nearly 50 inches in far southern Illinois to less than 35 inches across much of north-central Illinois. Large parts of far nothern and south-central Illinois were 1 to 5 inches wetter than normal last year, while much of central and far southern Illinois were 1 to 8 inches drier than normal.

The long-term Cooperative Observer station in Effingham recorded 56 inches of precipitation in 2022, making Effingham the wettest point in the state last year. Meanwhile, CoCoRaHS citizen science observers in LeRoy in McLean County and Mansfield in Champaign County recorded just 26 inches of precipitation in 2022. The year 2022 was the 21^st driest on record in Peoria with just 28.75 inches (76 percent of normal).

2022 Severe Weather

Last year was a mixed bag for severe weather. Most of our 102 counties were affected by strong wind, hail, or tornado events last year (Figure 6). Overall, the NOAA Storm Prediction Center showed 34 tornado reports, 104 hail reports, and 535 wind reports statewide in 2022. The 34 tornado reports in 2022 were well less than the 80 reports noted in 2021 and were the fewest tornado reports in Illinois since 2007.

Extreme precipitation and resultant flooding have become a mainstay in Illinois. Last year brought several very heavy precipitation events across the state. Among these events was a series of storms in the St. Louis area on July 26, producing several inches of rain in just a few hours. Parts of Cahokia Heights and Belleville caught 7 to 8 inches of rain in less than eight hours, causing widespread flooding (Figure 7). Based on state estimates of rainfall intensity probabilities, these totals in the Belleville area exceeded the estimated 0.2 percent annual exceedance, meaning this type of event has a 0.2% chance of occurring in any given year (https://www.weather.gov/lsx/July262022Flooding).

Just two weeks later, a swath of east-southeast Illinois between Effingham and Olney saw 7 to 10 inches of rain in less than 24 hours. The intense rainfall, centered over Newton in Jasper County, caused widespread flooding in nearly mature corn and soybean fields and riverine flooding along the Little Wabash and Embarras Rivers. Days later, a series of strong storms produced up to 11 inches of rain in less than 48 hours in parts of Jo Daviess and Stephenson counties in northwest Illinois. The rain inundated roads, flooded homes in and around Freeport, and caused flooding along the Pecatonica River (https://www.weather.gov/dvn/summary_080822).

Overall, 2022 brought its own set of unique conditions and weather. Despite daily and monthly variability in temperature and precipitation, most of the state was a bit cooler and drier than the 1991-2020 normal last year.

The preliminary statewide average December temperature was 29.4 degrees, 0.6 degrees below the 1991–2020 average and the 61^st coldest on record going back to 1895. The preliminary statewide average total December precipitation was 2.62 inches, 0.21 inches above the 1991–2020 average and 43^rd wettest on record statewide.    

Data are provisional and may change slightly over time.

Unusual Extreme Cold in Late December

December 2021 was the second warmest on record in Illinois. The unusually warm December weather was accompanied by tornado outbreaks, extreme rainfall, and the latest first measurable snowfall on record in Chicago (December 28^th). This year was quite a bit different, with much closer to, in not slightly warmer than normal temperatures in the first half of the month, followed by an extreme cold outbreak and rapid warmup in the second half. The plot of daily temperature departures from normal in Peoria shows the intensity of cold around Christmas, and how quickly extremely cold air was replaced with much warmer weather. In fact, Peoria went from -33 degree temperature anomalies on December 23^rd to +26 degree temperature anomalies on December 29^th, the quickest the city has experienced this magnitude of change on its 140+ year record.

A strong winter storm moved through the Midwest in late December, bringing extremely cold Arctic air into the region. Actual temperatures recorded in Illinois in the final two weeks of the month include -15 degrees in Knox and Mercer Counties, -12 degrees in Lee and Cook Counties, and -11 in McLean and Champaign Counties. Combined with 25+ mph sustained winds and 45+ mph wind gusts, wind chill values were in the -25 to -40 degree range. The extreme temperatures and wind chill values are very unusual for late December, only occurring in northern and central Illinois once every 20 to 25 years. As often happens, a strong ridge followed the intense trough in the jet stream, and the state warmed up quickly in the last week of the month. High temperatures ranged from the low 50s to mid-60s, between 10 and 25 degrees above normal.

When taken altogether, December average temperatures ranged from the low 20s in northern Illinois to the high 30s in southern Illinois, within 1 degree of normal (Figure 2). The warmest place in the state last month was Olmsted in Pulaski County with an average December temperature of 37.1 degrees. The coolest place in the state was Elizabeth in Jo Daviess County with an average December temperature of 22.4 degrees.

While no daily high maximum temperature records were broken last month, daily high minimum temperature records were broken at two stations. Meanwhile, the extreme cold in late December broke low maximum temperature records at 11 stations and low minimum temperature records at 5 stations. The station in Robinson in Crawford County set a new all-time December low temperature record of -9 degrees, breaking the old record of -8 degrees set in 1901.

Overall, the preliminary statewide average December temperature was 29.4 degrees, 0.6 degrees below the 1991–2020 average and the 61^st coldest on record going back to 1895.statewide.

Some Rain, Some Snow, and a White Christmas (for some)

Most of the state entered the first month of climatological winter drier than normal with some parts of southern Illinois having precipitation deficits of 8 to 10 inches going back to the summer. While December didn’t eliminate drought issues, the near normal precipitation last month put us on the road to drought improvement.

December total precipitation ranged from just under 2 inches in western Illinois to over 5 inches in far southern Illinois. Most of central and south-central Illinois was 0.5 to 1.5 inches drier than normal last month, while northern and southern Illinois were 0.5 to 1.5 inches wetter than normal. December was the first wetter than normal month since July in parts of far southern Illinois.

Overall, the preliminary statewide average total December precipitation was 2.62 inches, 0.21 inches above the 1991–2020 average and 43^rd wettest on record statewide.      

While the extreme temperatures and wind were the main storylines of the winter storm in late December, the storm did bring modest snowfall to the northern two-thirds of the state. A weaker storm system moved through the mid-South in early December, making for a snowier than normal December in southern Illinois, while snowfall totals were 1 to 5 inches below normal north of Interstate 64. The same snowfall pattern exists for the winter season to date, with areas north (south) of Interstate 64 having 1 to 5 inches below (above) normal snowfall.

Outlooks

Climate Prediction Center outlooks for January lean into a late-blooming La Niña-esque pattern, leaning to warmer and wetter than normal weather to kick off 2023 (Figure 6).  

The preliminary statewide average November temperature was 42.3 degrees, 0.6 degrees above the 1991–2020 average and tied for 45^th warmest on record going back to 1895. The preliminary statewide average total November precipitation was 1.92 inches, 1.40 inches below the 1991–2020 average and the 39^th driest on record statewide.    

Data are provisional and may change slightly over time.

November Temperature Swings

November began with unusually warm weather across the state. As Figure 1 shows, the first 10 days of the month were 5 to 20 degrees warmer than normal in Carbondale. A strong cold front moved through around November 11, ushering out the warmer air and replacing it with unusually cold air from Canada. The following 10 days between November 11 and the 20^th were 5 to 15 degrees colder than normal. November is known for intense temperature swings as we transition from fall to winter; however, this month’s swing was particularly extreme. For example, the average temperature in the first 10 days of the month was the 2^nd highest on record in Paducah, Kentucky. The following 10 days had an average temperature that was the 3^rd lowest on record. Temperatures moderated in the final 10 days of the month across the state.

Several places in the state had temperatures reach into the low to mid-80s in the first 10 days of November, including 82 degrees in Cahokia Heights and Cairo. Meanwhile, the cold air outbreak in the middle of the month brought nighttime low temperatures into the teens and single digits across the state, including 8 degrees in Monmouth and Champaign. Any place that missed out on a 28-degree hard freeze in October reached that mark multiple times in November.

November average temperatures ranged from the high 30s in northern Illinois to the low 50s in southern Illinois, within 1 degree of normal in the northern half of the state and between 1 and 3 degrees below normal in southern Illinois (Figure 2). The warmest spot in the state last month was Dixon Springs in Pope County with an average temperature of 46.7 degrees, and the coolest spot in the state was Elizabeth in Jo Daviess County with an average temperature of 38.7 degrees.

The warm start to November broke 50 daily high maximum temperature records and broke 4 daily high minimum temperature records last month. The subsequent cold weather broke 30 daily low maximum temperature records and broke 27 low minimum temperature records last month.

Overall, he preliminary statewide average November temperature was 42.3 degrees, 0.6 degrees above the 1991–2020 average and tied for 45^th warmest on record going back to 1895.

A Mild Fall

Fall 2021 was the 10^th warmest on record statewide, including the 4^th warmest October on record statewide. Although some may enjoy an extension of summer, the unusually warm weather last year challenged many of the fall activities. In contrast, we enjoyed mild temperatures this fall, making for a great season to be outdoors in Illinois. As Figure 3 shows, September was within 1 degree of normal statewide, October was 1 to 3 degrees cooler than normal, and November was near to slightly cooler than normal statewide.

Overall, the statewide fall 2022 average temperature was 54.1 degrees, 0.1 degrees below the 1991–2020 normal and tied for 64^th coolest on record.

Dry November Didn’t Bring Drought Help

November is typically one of our drier months outside of the winter, so we don’t expect November to make a big dent in precipitation deficits from the summer and fall. This year November played to type and continued the drier than normal weather streak for most of the state. Total November precipitation ranged from nearly 4 inches in northwest Illinois to less than 1.5 inches in east-central and southeast Illinois. Only the northwest sliver of the state was wetter than normal last month, while southeast Illinois was 2 to 3 inches drier than normal (Figure 4).

Despite the drier weather in November, virtually all the state saw near to above normal snowfall last month. As Figure 5 shows, November snowfall totals ranged from over 7 inches in southwest Illinois to just less than 1 inch in central Illinois. All areas south of Interstate 80 had above normal snowfall, while northern Illinois had just less than normal November snowfall.

A strong low-pressure system swung through the middle Mississippi region in mid-November and brought sometimes heavy snow to the St. Louis Metro East area. Parts of Belleville, Mascoutah, and Breese picked up between 6 and 8 inches of snow in just a few hours. Waterloo in Monroe County had 8.4 inches of snow last month–most of which came from that one storm–making it the 2^nd snowiest November on record there (after 1980). The November snowfall in southern Illinois was not only unusually heavy, but was also abnormally early, especially in far southern Illinois. Paducah, Kentucky–just across the Ohio River from Brookport in Massac County–had its first measurable snow on November 11 this year, the 3^rd earliest on record.

Drought Continues

Outside of parts of southwest, east-central, and northwest Illinois that experienced very heavy rain in mid- to late summer, most of Illinois has been somewhat to much drier than normal since July. Long-term precipitation deficits are largest in southern Illinois, where areas from Carbondale to Metropolis have had only 50–60 percent of normal rainfall since July 1.

Unfortunately, the mild fall temperatures were accompanied by drier weather, extending drought conditions across the state. As Figure 5 shows, most parts of the state were drier than normal in at least two of the three fall months, and all three months were drier than normal in southern Illinois.

The result of the dry weather was a continuation–and in some cases, worsening–of drought conditions across the state. The latest U.S. Drought Monitor shows severe to extreme drought across southern Illinois and moderate drought in north-central and northeast Illinois. Although ecological impacts have diminished as we move closer to winter, drought impacts to hydrology have continued. These impacts include low stream, lake, and pond levels across the state and low flow on the Illinois and Mississippi Rivers.

Overall, the preliminary statewide total November precipitation was 1.92 inches, 1.40 inches below the 1991–2020 average and the 39^th driest on record statewide. The 2022 fall season preliminary total precipitation was 6.84 inches, 2.58 inches below normal and the 28^th driest on record since 1895.

Looking Forward to December & Winter

December is the start to climatological winter and when we typically begin to see our more interesting winter weather. The current Climate Prediction Center outlook for the month of December leans toward cooler than normal weather for the last month of the year. While the outlook leans drier than normal in northern Illinois, there are higher chances for wetter than normal weather in drought-stricken southern Illinois (Figure 7).

Meanwhile, outlooks for the winter season, December through February, lean more into ongoing La Niña patterns, including higher chances of wetter than normal conditions in winter (Figure 8). If La Niña plays to type and we do see a wetter winter, it would be beneficial for removing or reducing drought across the state. With that said, previous La Niña winters tend to be “back-loaded,” meaning we don’t see the strongest signals until January and February.