Lake County, IL

Alerts

Advisory Area
County Line

Alerts are listed in order of start time and level of severity. Click on the alert title to read details for each alert.

In effect from Monday 07/27 4:44 PM CDT – Wednesday 07/29 10:00 AM CDT

Issued by NWS Chicago IL

What

Thunderstorm activity through late this afternoon will create varying currents, rapid water level fluctuations, and dangerous swimming conditions with waves 3 to 5 feet expected. Northerly winds will develop tonight and create high wave action and dangerous swimming conditions with waves 6 to 9 feet expected.

Where

In Illinois, Lake, Northern Cook and Central Cook Counties. In Indiana, Lake and Porter Counties.

When

Through Wednesday morning.

Impacts

Swimming conditions will be life threatening, especially for inexperienced swimmers. For information on swim advisories or bans at Chicago beaches: www. cpdbeaches. com.

What to Do

Remain out of the water to avoid dangerous swimming conditions and do not venture out onto piers, jetties, breakwalls, or other shoreline structures.


Areas Impacted

  • Lake
  • Northern Cook
  • Central Cook
  • Lake
  • Porter

Tips to Stay Safe

Your area may see dangerous swimming conditions. Use caution: 

  • Stay off of rocks and jetties due to dangerous conditions
  • Stay out of the water to avoid hazardous swimming conditions, and stay near occupied lifeguard towers 
  • Keep small children in sight and within arm’s reach at all times.

Briefing

Last updated

From the Forecaster

Five Day Outlook

Created by the NWS Chicago WFO

Expect dangerously hot and humid conditions today with afternoon heat indices pushing 110°F or higher! Additionally, thunderstorms may develop during the PM hours, some of which may become strong or severe.

This is a multiday forecast graphic for northern Illinois and northwest Indiana.  Headline: Five Day Outlook.  Sub Headline: Hot and humid today with some strong PM storms possible.  Peak heat indices*.  ~110°+ around and west of I-39.  ~100° to locally 110° elsewhere in N IL and NW IN.  Severe Storm Potential.  Heat and Humidity Today.  Storms may develop this afternoon and evening.  *If storms develop, they may become severe with  damaging winds and large  hail.  Visit weather.gov/Chicago for more forecast details for your location.    Graphic Created: Monday, July 27, 2026 7:17 AM CDT

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.

risk level
out of 10
out of 10
out of 10
out of 10
table legend
No risk
Low risk
High risk

Weather Forecasting Office

Chicago Forecast Office

Find a Forecast