Week of March 29, 2026
Marengo Weather: The Week Ahead
Spring teases, then pulls back hard
Spring can't make up its mind. We open the week mild, push into the upper 70s Monday and Tuesday, and then watch the bottom fall out: by Thursday, highs drop into the low 30s with snow in the forecast. A 50-degree swing in four days. Even for northern Illinois, that's a lot.
Day by Day
Sunday
March 29We open the week at 65° under overcast skies, with lows near 39°. That's about 17 degrees above the seasonal average of 48° for late March in Marengo. Enjoy it. Wind out of the southwest at 16 mph. Dry all day.
Monday
March 30Here's where it gets interesting. Highs jump to 79°, which is closer to mid-May than late March. The warm air rides ahead of a front that's still a couple days out. Clouds build through the day, and winds pick up to 21 mph with gusts higher. A stray shower is possible late, but most of the day stays dry.
Tuesday
March 31The front's influence starts to show. Still warm at 75°, but rain moves in: 73% chance, and it could be heavy at times. Winds stay gusty at 23 mph. This is the last of the warm air. Lows drop to 52° overnight as the cold starts filtering in behind the front.
Wednesday
April 1The crash begins. Highs fall 25 degrees to just 50°, and it feels worse with 21 mph winds. Rain chances linger at 60%. The seasonal average for April 1 in our area is about 53°, so we're right at normal, but coming off 75° yesterday, it'll feel raw. Lows near 32°.
Thursday
April 2The cold deepens. Highs reach only 33° with lows near 23°. That's 20 degrees below the seasonal norm. Snow is likely, 70% chance, and winds at 21 mph will make it feel even colder. If you're still thinking about garden planting, hold off.
Friday
April 3Slow recovery starts. Highs reach 40°, still well below normal. Rain or mixed precipitation at 50% chance. The worst of the cold is behind us, but it's not pleasant. Fog possible in the morning.
Saturday
April 4We end the week back near 65°, a 32-degree rebound from Thursday. The pattern is trying to reset toward spring, but this kind of volatility is the signature of late March in the Midwest. Rain chances at 55% as another system moves through. Lows near 35°.
The Bottom Line
The big story this week is the temperature whiplash. Monday-Tuesday will feel like May, but by Thursday you'll need a winter coat again. The cold snap is real but brief. By Saturday we're clawing back toward seasonal averages. If you have outdoor plans, front-load them early in the week.