Overview
Temperatures averaged 43.9 degrees in November, 1.8 degrees above the 30-year normal and tied for the 28th warmest on record statewide (Figure 1).
Precipitation statewide in November was 1.96 inches, 1.12 inches below the 30-year normal, the 42nd driest November on record statewide (Figure 1).
Soil moisture at 2-inch depths averaged 0.30 water fraction by volume (wfv) at the end of November, 17% higher than the beginning of the month. Moisture levels increased 8% at 4-inches and remained steady at depths of 8-inches and greater.
Shallow groundwater levels were 2.12 feet below the long-term average at the end of November. Levels averaged 0.03 feet above October and 1.18 feet below last year (Figure 1).
Mean streamflow statewide was below the median for the month.
Mean provisional streamflow aggregated statewide was below the long-term median flow for November, about 50% of median (Figure 1). Monthly mean discharge values ranged from normal to much below normal for November. The November 2025 monthly mean flow of the Sangamon River at Monticello was the lowest reported for any calendar month in the record of the streamgage (Figure 1).
Water surface levels at the end of November were below the full pool or target level at 18 of 19 reporting reservoirs. At the end of November, Lake Shelbyville was 2.7 feet below the December 1 target level, Carlyle Lake level was 0.7 feet below the December 1 target level, and Rend Lake was 0.9 feet below the spillway level.
Lake Michigan’s mean level was below its long-term mean for the month.
Weather/Climate Information (Trent Ford)
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.
November and climatological fall in Illinois were warmer and drier than normal statewide.
Temperatures averaged 43.9 degrees in November, 1.8 degrees above the 30-year normal and tied for the 28th warmest on record statewide. November average temperatures ranged from the high 30s in northern Illinois to the high 40s in southern Illinois, which despite the late month cool down, was 1 to 3 degrees warmer than normal (Figure 2, Table 1a). Several stations saw high temperatures push into the high 70s and even low 80s in the middle of the month, including 80-degree highs in Cahokia Heights and Morrisonville. Meanwhile, the last week of the month brought some very low nighttime minimum temperatures, including 11 degrees in Rockford and 15 in Galesburg. The coldest point in the state last month was Stockton at 38 degrees, and the warmest point was Smithland Lock and Dam in Massac County at 49.1 degrees.
Precipitation statewide in November was 1.96 inches, 1.12 inches below the 30-year normal, the 42nd driest November on record statewide. September and October were both dry months across Illinois, especially in the northern half of the state. While November wasn’t a washout by any means, some of the drier areas of the state did get significantly more precipitation, in many forms. Total precipitation last month ranged from nearly 6 inches in central Illinois to less than 2 inches in east-central Illinois (Figure 3, Table 1a). Much of northern Illinois and parts of central Illinois were 1 to 4 inches wetter than normal, while most of southern Illinois was 1 to 3 inches drier than normal. Some of the more impressive November totals include 7.48 inches in Streator and 7.41 inches in Lombard.
Snow: Snowfall in November is not a rare occurrence but certainly is not a mainstay in Illinois. This year, the northern half to two-thirds of the state experienced moderate snowfall in the final few days of the month. Earlier in November, unusually intense lake-effect snowfall accumulated in the eastern half of the state, stretching all the way down to Evansville, Indiana. November snowfall ranged from nearly 18 inches in far northeast Illinois to no measurable snowfall in much of southern Illinois. The two big rounds of snowfall last month made for much more snow than average November for central and northern Illinois. Last month was a top 10 snowiest November on record in many places, including the sixth snowiest in Rockford (10.0 inches) and Moline (9.2 inches), the fifth snowiest in Champaign-Urban (8.4 inches), and the third snowiest in Springfield (8.9 inches).
Fall: Climatological fall’s (September – November) average temperatures ranged from the low 50s in northern Illinois to the low 60s in southern Illinois, between 1 and 5 degrees warmer than normal. It was a top 10 warmest fall in many places including the sixth warmest in Champaign-Urbana and Salem. Overall, the statewide average temperature in fall was 57.5 degrees, 3.0 degrees above the 1991-2020 normal and the seventh warmest fall on record in Illinois (Table 1b).
Fall season total precipitation ranged from over 14 inches in southern Illinois to less than 4 inches in east-central Illinois. Only parts of southern Illinois were wetter than normal, while much of central and northern Illinois were 4 to 7 inches drier than average. Last season was a top 10 driest fall on record in Peoria (3.67 inches), Danville (3.81 inches), Decatur (4.73 inches), and Galesburg (4.43 inches). Overall, the statewide fall total precipitation was 5.74 inches, 3.95 inches below the 1991-2020 normal and 13th driest fall on record in Illinois (Table 1b). Last season was also the sixth consecutive drier than normal fall in Illinois.
Illinois Climate Network (ICN) (Jennie Atkins)
The Illinois Climate Network (ICN) consists of 20 stations across the state which collects hourly weather and soil information.
Winds rose again in November to an average of 7.0 mph, 1.4 mph higher than October but 08 mph lower than the network’s long-term average. ICN Bondville (Champaign County) had the windiest month, averaging 11.2 mph, closely followed by ICN Monmouth (Warren County) and ICN Stelle (Ford County) each averaging 11.1 mph. The highest recorded wind gust was 49.7 mph that was measured at ICN Stelle on November 26.
Temperatures fell 15° from October to a network average of 44.0°, 1.6° higher than the long-term average. Station highs ranged from the low 80s to high 60s with lows from the mid-20s to single digits. The highest temperature was 80.4°, reported at ICN Belleville (St Clair County) on November 15. ICN St Charles (Kane County) measured 5.9° on November 30, the month’s lowest temperature.
Soil temperatures were 13 to 15° lower in November with averages in the mid-40s to low 50s. Under bare soils, temperatures ranged from 24.1 to 72.0° at 2 inches and 24.9 to 68.6° at 4 inches. Temperatures under sod ranged from 33.7 to 60.5° at 4 inches and 29.9 to 65.0° at 8 inches.
November was drier for most stations as only two – ICN Big Bend (Whiteside County) and ICN St Charles (Kane County) – had totals higher than their long-term average. Overall, the network averaged 2.04 inches for the month, 1.05 inches less than October and 0.87 inches lower than the long-term average.
The highest totals were in the south where ICN Olney (Richland County) recorded 2.81 inches, the month’s highest total.
Despite the lower precipitation, lower temperatures led to higher soil moisture levels across the network at least at the shallower depths. Two-inch soil moisture rose 17% on average during the month. All regions showed increases with the highest being in the north.
Higher moisture levels were also seen at 4 inches, However at 8 inches and deeper, soil moisture remained steady in November.
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 past record of monthly mean flows at those stations for the same month. Both recent and long-term data are retrieved from 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.)
Mean provisional flow aggregated statewide, using the available monthly mean data shown this month in Table 2, was below the median value for November (approximately 50 percent of the median) and below the mean for November (approximately 30 percent of the mean). In November, monthly mean discharge values ranged from normal to much below normal. The November 2025 monthly mean flow of the Illinois River at Valley City was the lowest reported for the calendar month of November in the period of record of the station (86 years). The November 2025 monthly mean flow of the Sangamon River at Monticello was the lowest reported for any calendar month in the record of the streamgage (116 years of record).
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 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-October water levels at 19 reservoirs for which levels were reported last month and this month, reported end-of-November water levels were lower at 13 reservoirs, higher at 3 reservoirs, and about the same as at the end of October at 3 reservoirs. For the 18 reservoirs with measurements reported for the end of November, water levels were below normal target pool or spillway level at 16 reservoirs, and above normal target pool or spillway level at 1 reservoir (which is no longer a water supply reservoir).
Major Reservoirs. Compared to water levels at the end of October, at the end of November the water level at Rend Lake was 0.5 feet lower, Lake Shelbyville was 0.4 feet lower, Carlyle Lake was at about the same level as at the end of October. At the end of November, Lake Shelbyville was 2.7 feet below the December 1 target level, Carlyle Lake level was 0.7 feet below the December 1 target level, and Rend Lake was 0.9 feet below 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 November 2025 mean level for Lake Michigan was 577.9 feet. The monthly mean level one year ago (November 2024) was 578.5 feet. The long-term average lake level for November is 578.8 feet, based on 1918-2023 data. In this period of record, the lowest mean level for Lake Michigan for November occurred in 1964 at 576.3 feet, and the highest mean level for November occurred in 1986 at 582.0 feet. The month-end level of Lake Michigan was 577.6 feet. All values are provided by the U.S. Army Corps of Engineers Detroit District.
Groundwater Information (Jennie Atkins)
Water table levels averaged 0.03 feet higher than October. Fourteen stations declined in November, most less than a foot. Nine wells increased over the month, the majority above 1’. The largest increases were in the south where the Carbondale well (Jackson County) ended the month 2.08’ higher.
Levels were lower than last year. Fifteen wells in all regions had levels lower than November 2024 with nine of those lower 2’ or more. The largest decrease was at the Belleville well (St Clair County) that was 5.47’ lower.
Wells averaged 1.18 feet below November 2024, 2.08 feet below the 15-year average, and 2.12 feet below the long-term record (Table 4). November was the 11th month with water tables averaging lower than the long-term record.
Data sources for the IWCS include the following:
CPC - Climate Prediction Center
ISWS - Illinois State Water Survey
MRCC - Midwestern Regional Climate Center
NCEI - National Centers for Environmental Information
NWS – National Weather Service
SPC – Storm Prediction Center
USACE – U.S. Army Corps of Engineers
USDM – US Drought Monitor
USGS – US Geological Survey
WARM – Water and Atmospheric Resources Monitoring Program