McHenry County, IL

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From the Forecaster

High Swim Risk Tonight and Wednesday

Heads up! Dangerous swimming conditions are expected to develop at southern Lake Michigan beaches this evening and last through Wednesday night, possibly stretching into early Thursday. Please plan accordingly if you're heading to the beach! weather.gov/greatlakes/beachhazards.

Image Description

Headline: High Swim Risk Tonight - Wednesday. Sub Headline: Stay dry when waves are high! What To Expect. Dangerous waves up to 10 feet and hazardous boating conditions. Life threatening currents. This evening through Wednesday. Choppy, less-than-favorable conditions this afternoon may be dangerous for weak swimmers. Southern Lake Michigan Beaches. In Illinois and northwest Indiana. What To Do. Stay out of the water! Obey posted signs and closures. Avoid piers, breakwalls, and lakeshore trails. For beach forecasts: weather.gov/greatlakes/beachhazards Graphic Created: Tuesday, July 21, 2026 2:53 AM CDT

Chicago Area Forecast Discussion

Seven-day Weather Risk Overview

The graphic shows the daily risk summary for 7 days. Daily risk is based on highest risk factor for that day.

	Tue 7/21	Wed 7/22	Thu 7/23	Fri 7/24	Sat 7/25	Sun 7/26	Mon 7/27
risk level						out of 10	out of 10

No risk

Low risk

High risk

See the detailed risk analysis

Radar

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dBz	Intensity
−35–0	Extremely light (drizzle/snow)
0–20	Very light precipitation or general clutter
20–40	Light precipitation
40–50	Moderate precipitation
50–65	Heavy precipitation or some hail
>65	Extremely heavy precipitation including water-coated hail

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Chicago Forecast Office