Cold November Brings an End to Meteorological Autumn

November temperatures were well below the long-term average across the state, breaking hundreds of local daily records. The preliminary statewide November average temperature was 35.6 degrees, about 7 degrees below our 30-year normal and tied for the ninth coldest on record. Preliminary data suggest November was drier than average for most of the state. The statewide average November precipitation total was 2.51 inches, approximately 0.96 inches below the 30-year normal.

Data are provisional and may change slightly over time

Cold Weather

The intense cold weather at the end of October continued into the first two thirds of November. Average temperatures ranged 10 to 15 degrees below the long-term mean for the first half of the month. Between November 1 and November 15, 149 daily low maximum temperature records and 177 daily low minimum temperature records were broken across the state. Several all-time November temperature records were broken as well, including both the all-time November low minimum and low maximum temperature records in Robinson, Illinois (Crawford County, records back to 1893). At Chicago’s O’Hare airport, 22 out of 30 November days experienced an average temperature below the long-term mean, including the first 19 days of the month. Stations in Knox, Jo Daviess, Carroll, and Whiteside Counties observed daily minimum temperatures below 0 in November, the lowest being -4 degrees in Altona (Knox County) on November 7.

A shift in the upper-atmospheric trough around November 20 allowed temperatures to moderate. Average temperatures between November 16 and November 30 were between 1 and 3 degrees below normal across the state. Overall, November temperatures were between 4 and 8 degrees below the long-term mean across the state. The preliminary 2019 statewide November average temperature was 35.6 degrees, which was also the 2018 statewide average temperature and tied for the ninth warmest November on record.

Precipitation

November precipitation was below the long-term mean for all of Illinois north of Interstate 64. Monthly precipitation totals ranged from 1 to 2 inches in central and northern Illinois to over 6 inches in far southern Illinois. These totals represented between 2 inches below normal and 2 inches above normal.

The statewide average precipitation total for November was 2.51 inches, approximately 1 inch below the 30-year normal and 56th driest monthly total since 1895. November was only the second month this year–along with July–that experienced below normal statewide average precipitation and only the third month since June 2018 (see figure below).

Despite the dryness, abundant October precipitation and timely rain and snow events throughout November alleviated all abnormally dry conditions across the state. According to the U.S. Drought Monitor, the entire state has been free of drought and abnormally dry conditions since November 5.

Although total precipitation was below normal for most of the state this last month, snowfall totals were well above average. Total November snowfall accumulations ranged from nearly 12 inches in northern Illinois to just over half an inch in far southern Illinois. Accumulations were between 1 and 6 inches below the long-term November average snowfall totals. Measurable snowfall (accumulation greater than 0.10 inches) occurred in November as far south as Cairo (Alexander County). The highest November snowfall total was 11.7 inches in McHenry County.

Just as impressive as the snowfall totals this month was the number of days with measurable snowfall. The long-term weather station in Freeport recorded 5 days in November with measurable snowfall, tied for the second most since 1948 and the most since 1978.

December Outlooks

Both short-term 8- to 14-day outlooks and 1-month December outlooks from the Climate Prediction center show strongly elevated odds of above normal temperatures across the state. The outlooks are informed in part by predicted changes in mid-level atmospheric pressure patterns in early December, which permit southerly movement of warm air into the region.

The shorter and longer outlooks both show slightly elevated odds of above normal precipitation, although odds are weaker than for temperature outlooks. Winter (December–February) outlooks show an equal chance for temperature and slightly elevated odds for above normal winter precipitation.