Warm and Wet November Wraps Up Fall – Illinois State Climatologist

The preliminary statewide average November temperature was 46.6 degrees, 4.4 degrees above the 1991-2020 average and tied for the 10^th warmest on record going back to 1895. The preliminary statewide average total November precipitation was 4.15 inches, 1.07 above the 1991-2020 average and the 20^th wettest on record statewide.

Data are provisional and may change slightly over time.

Mild November with a Chilly End

November can be a challenging month for those yearning for summer to come back. However, as daily average temperature departures in Jacksonville show, the past month brought mostly mild temperatures that felt more like early fall than early winter (Figure 1). Several days in the first and third weeks of the month were 10 to 20 degrees warmer than normal. Thanksgiving week brought a big temperature change on the back of a strong cold front. The last few days of the month saw temperatures that that were 5 to 15 degrees below normal, including several nighttime low temperatures in the teens.

**Figure 1**. Daily November average temperature departures in Jacksonville.

November temperatures ranged from the low 40s in northern Illinois to the mid-50s in southern Illinois, around 2 to 7 degrees above normal (Figure 2). Several places saw high temperatures into the high 70s in early to mid-November, including 79 degrees in Decatur and Marseilles. Meanwhile, the last week of the month brought some very low temperatures, including 7 degrees in Stockton and 9 degrees in DeKalb. The coldest point in the state last month was Stockton at 41.2 degrees, and the warmest point was Du Quoin at 53.3 degrees.

**Figure 2**. Maps of (left) November average temperature and (right) November average temperature departures from normal.

Much November Rain for Which to Be Thankful

September and October were both very dry months across Illinois, outside of the few places that saw rain from the remnants of hurricane Helene. November flipped that script and brought quite a bit of rain across much of the state. November totals ranged from over 8 inches in the St. Louis Metro East area to around 3 inches in north-central Illinois. Parts of southwest and central Illinois were 5 to 8 inches wetter than normal last month, while much of far southern Illinois was 1 to 2 inches drier than normal (Figure 3). Some of the more impressive November totals include 9.97 inches in Granite City and 8.38 inches in Cahokia Heights. Meanwhile, Moline and Rockford only picked up around 2 inches total for the month. Last month was the wettest November on record in Edwardsville with 9.97 inches, and it was the first November since 1946 with over 9 inches of rain in Edwardsville.

**Figure 3**. Maps show (left) November total precipitation and (right) precipitation departure from normal across Illinois.

Overall, the preliminary statewide average total November precipitation was 4.15 inches, 1.07 above below the 1991-2020 average and the 20^th wettest on record statewide.

Some Snow, At Least

Snowfall in November is not a rare occurrence, but certainly is not a mainstay in Illinois. This year, the northeast corner of the state was the big “winner” for pre-Thanksgiving snowfall, with lake-enhanced snow contributing to widespread 1.5 to 3 inch totals across the Chicagoland area last month. The Interstate 64 corridor also picked up between a quarter and half an inch of snow in the final week of November (Figure 4). Otherwise, the three months comprising climatological fall (September through November) were snow free. Fall snowfall deficits ranged from near 3 inches below normal in northwest Illinois to less than half an inch below normal in the St. Louis Metro East area (Figure 4).

**Figure 4**. Maps show (left) November total snowfall and (right) snowfall departure from normal for climatological fall across Illinois.

A Mild Fall in Illinois

Climatological fall includes September, October, and November, and — for my money — it is the best weather season Illinois has to offer. This past season’s average temperatures ranged from the mid-50s in northern Illinois to the low 60s in southern Illinois, between 2 and 5 degrees above normal (Figure 5). It was a top 10 warmest fall on record in most parts of the state, including the third warmest fall on record in Chicago, the fourth warmest on record in Peoria, and the fifth warmest on record in Champaign-Urbana. Champaign had only nine nights with minimum temperatures below freezing, which was the fewest since 1973 and the fourth fewest on record.

Overall, the preliminary statewide average temperature in fall was 57.9 degrees, 3.3 degrees above the 1991-2020 normal and the fourth warmest fall on record in Illinois.

**Figure 5**. Maps show (left) average temperatures and (right) temperature departures for climatological fall.

Fall season total precipitation ranged from over 15 inches in southwest Illinois to less than 4 inches in parts of north-central Illinois. Only the southwest part of the state was wetter than normal, while the rest of the state was 1 to 6 inches drier than normal this fall (Figure 6). It was a top 10 driest fall on record in Freeport (4.47 inches), Moline (3.77 inches), and Galesburg (4.52 inches).

Overall, the preliminary statewide fall total precipitation was 7.88 inches, 1.81 inches below the 1991-2020 normal and the 48^th driest fall on record in Illinois. It was also the fifth consecutive drier-than-normal fall in Illinois.

**Figure 6**. Maps show (left) maps of total fall season precipitation and (right) fall precipitation departures from normal.

Outlooks

Welcome to winter! December brings in the coldest, snowiest season of the year. Climate Prediction Center outlooks for the month of December don’t show any strong signals for Illinois, with equal chances of a warmer, colder, drier, and wetter than normal end to 2024 (Figure 7a). Outlooks for climatological winter (December through February) are a bit more telling, with better chances of wetter than normal winter weather (Figure 7b).