A cold front with heavy rain and thunderstorms is setting up a wide area of wintry conditions in the Midwest. The air temperature in northern Illinois dropped more than 20°F in less than an hour starting around 4:00 p.m. in Arlington Heights, as an outflow boundary moved southeast east across northern Illinois.
There is a Blizzard Warning for Illinois counties north and west of McHenry County, De Kalb County, Lee County, Bureau County, Putnam County, and Knox County, Additionally there are many counties in Iowa, Minnesota, Wisconsin, South Dakota, and Nebraska with a Bizzard Warning activated.
At 7:22 p.m. Sunday, March 15, 2026, the National Weather Service (NWS) upgraded a Winter Storm Warning to a Blizzard Warning for counties in northwest and central Illinois. The NWS also included Dekalb and McHenry counties in this warning. The NWS also expanded the Winter Weather advisory anther row of counties southeastward along the
I-55 corridor.
Periods of accumulating snow and blowing snow will set the stage for Blizzard conditions across northwestern IL overnight into Monday morning. We have thus opted to upgrade to a Blizzard Warning across parts of northwestern IL. A Winter Weather Advisory remains in effect for areas along and northwest of the I-55 corridor overnight through Monday morning.
Arlington Heights and O’Hare International Airport is under a Winter Weather Advisory. McHenry, Illinois is forecast to get about 3.6 inches of snow by 7:00 p.m. Monday, while Arlington Heights is forecast to get about 3.1 inches of snow by 10:00 p.m. Monday.
Weather Radarat 8:30 PM showed moderate to heavy rain precipitation strengthening or maintaining intensity and moving east and internally moving northeast.
Clearing skies in North and South Dakota, Nebraska, and Kansas.
See also Arlingtoncardinal.com/clouds
MCHENRY, IL FORECAST …
Sunday Night: Rain showers, freezing rain, and sleet before 11pm, then snow showers, possibly mixed with sleet between 11pm and midnight, then snow showers after midnight. Patchy blowing snow after 1am. Low around 20. Windy, with a north wind 20 to 30 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. Total nighttime ice accumulation of less than a 0.1 of an inch possible. Total nighttime snow and sleet accumulation of 1 to 3 inches possible.
Monday: Snow showers before 1pm, then a chance of snow, mainly between 1pm and 4pm. Areas of blowing snow. High near 22. Windy, with a northwest wind 25 to 30 mph, with gusts as high as 45 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible.
Monday Night: Patchy blowing snow before 7pm. Cloudy, then gradually becoming partly cloudy, with a low around 7. Wind chill values as low as -7. Blustery, with a west northwest wind 10 to 20 mph, with gusts as high as 30 mph.
Tuesday: Mostly sunny, with a high near 22. Wind chill values as low as -7. West northwest wind around 10 mph, with gusts as high as 15 mph.
Tuesday Night: Snow showers likely, mainly after 1am. Mostly cloudy, with a low around 17. South wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Wednesday: Mostly cloudy, with a high near 41.
Wednesday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 32.
Thursday: Mostly sunny, with a high near 50.
Thursday Night: Mostly cloudy, with a low around 34.
Friday: Partly sunny, with a high near 59.
Friday Night: Mostly cloudy, with a low around 38.
Saturday: Mostly sunny, with a high near 57.
Saturday Night: Partly cloudy, with a low around 35.
Sunday: Partly sunny, with a high near 50.
ARLINGTON HTS DOWNTOWN …
Sunday Night: Rain, possibly mixed with sleet before midnight, then snow. Patchy blowing snow after 1am. Low around 22. Windy, with a north wind 20 to 30 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. Total nighttime snow and sleet accumulation of 1 to 3 inches possible.
Monday: Snow, mainly before 1pm. Patchy blowing snow. Temperature falling to around 22 by 8am. Windy, with a northwest wind 25 to 30 mph, with gusts as high as 45 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible.
Monday Night: A 10 percent chance of snow before 7pm. Cloudy, then gradually becoming partly cloudy, with a low around 10. Wind chill values as low as -3. Blustery, with a northwest wind 15 to 20 mph, with gusts as high as 30 mph.
Tuesday: Mostly sunny, with a high near 24. Wind chill values as low as -4. West northwest wind around 10 mph, with gusts as high as 20 mph.
Tuesday Night: Snow showers likely, mainly after 1am. Mostly cloudy, with a low around 19. South wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Wednesday: Mostly cloudy, with a high near 42.
Wednesday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 33.
Thursday: Mostly sunny, with a high near 52.
Thursday Night: Mostly cloudy, with a low around 36.
Friday: Partly sunny, with a high near 60.
Friday Night: Mostly cloudy, with a low around 39.
Saturday: Mostly sunny, with a high near 57.
Saturday Night: Partly cloudy, with a low around 37.
Sunday: Partly sunny, with a high near 51.
LAKE TEMPS …
Southern Lake Michigan Water Temperatures
National Weather Service Chicago/Romeoville IL
858 AM CDT Sun Mar 15 2026
Lake Michigan Water Temperatures…
Chicago Shore………..40.
Chicago Crib…………42.
Michigan City………..38.
South Mid Lake Buoy…..38.
&&
M is for missing data that is normally available. Chicago Shore, Chicago Crib, and Michigan City are read every day of the year.
Measured at a depth of 60 ft for Chicago Crib and 30 ft for Michigan City. May not represent surface temperature.
march.chicagoweatherstation.com
Chicago Weather Forecast for your MAC/PC/TABLET includes surrounding suburbs.
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