The National Weather Service has issued an Extreme Heat Watch for Evanston and Cook County, in effect from noon Monday, June 29, through 10 p.m. Wednesday, July 1. Afternoon heat index values are expected to exceed 100°F, and forecasters warn the dangerous heat will persist through at least Thursday, July 3.

Highs in the Chicago area are forecast to reach 92°F Tuesday, 94°F Wednesday, and 95°F both Thursday and Friday, according to the National Weather Service forecast reported by Patch. AccuWeather forecasts at least five consecutive days at or above 90°F for Chicago.

Overnight temperatures offer little relief. NOAA forecasters wrote that overnight lows will remain "quite warm, with some record high minimums possible, bringing little to no relief from the heat in the nighttime hours." The NWS point forecast for Evanston already shows a Sunday night low of 71°F before the dome fully arrives.

Nexstar meteorologist Blake Matthews called the event "the first widespread, significant heat wave of 2026 for much of the South and Midwest," with the heat dome's high-pressure ridge forecast to center nearly over Chicago by Saturday, July 4. If the forecast holds, CBS Chicago reported it would be the longest run of days above 95°F in the area in 14 years.

Who is most at risk

The NWS identifies young children and infants, older adults living alone or with limited mobility, people with chronic medical conditions, and pregnant women as most vulnerable during extreme heat. The agency warns it is never safe to leave a child, disabled person, or pet locked in a car.

How to stay safe

The Weather Service advises staying indoors in air conditioning whenever possible. If you must go outside, "go early or late in the day, and dress in light-colored clothing," the agency said. The CDC recommends drinking eight ounces of water every 15 to 20 minutes when working outdoors.

Cooling resources

As of Friday, June 27, the City of Evanston has not announced specific cooling center activations for the coming week. Residents can call 311 or check cityofevanston.org for updates. Evanston Public Library branches and the Robert Crown Community Center are air-conditioned public spaces that have historically served as cooling sites during heat emergencies. Residents should confirm hours and availability.

The Extreme Heat Watch may be upgraded to a warning as the event approaches.