Today’s temperatures are expected to reach a high of 89 degrees before dropping to a low of 62 degrees Saturday night.

The National Weather Service also issued an air quality alert that will remain in effect until midnight Saturday. The Illinois Environmental Protection Agency first issued an “air pollution action day” for the city of Chicago and surrounding areas on Friday. This indicates that ozone levels may be particularly unhealthy for sensitive groups.

Officials warn that those with pulmonary or respiratory diseases should limit prolonged outdoor activity until the alert concludes.

There is a slight thunderstorm risk today and tonight, officials said.