CHICAGO (CBS) — The outside world feels like the steam room at your local fitness center again, as the temperature nears 100 degrees for another day.

CBS 2 Meteorologist Ed Curran says it was 87 degrees at O’Hare International Airport, 90 at Midway, and 92 at Northerly Island as of 11:20 a.m. But with dew points of 66 at O’Hare and as high as 72 in DeKalb, the resulting heat indices made the humid, muggy air feel like 96 at the lakefront, 92 at Midway, and 90 at O’Hare.

Cloud cover has been hovering over the area from a round of storms that passed over Wisconsin. The storms almost hit the northern suburbs, but not quite.

The high for the day is 99 degrees, and only the chance of a thunderstorm later stands a chance of breaking up the humidity.

A heat advisory is in effect through 7 a.m. Wednesday, at which point an excessive heat watch begins for Cook County – meaning a prolonged period of hot temperatures is expected. Parts of southern Wisconsin, northern Indiana and southeast Michigan are under an excessive heat warning, meaning prolonged hot conditions will occur for sure.

The heat and high humidity can cause a dangerous situation, in which heat illnesses are possible. Anyone who has to be outside is advised to drink plenty of fluids, wear loose-fitting clothing, and stay out of the sun.

Checking up on relatives is also necessary under conditions such as these, the weather service emphasizes.

For the Fourth of July, the high is again 99. But the temperature could reach 100 both Tuesday and Wednesday, particularly in high-density city areas.

The high for Thursday is 98, and Friday stands to be the second official triple-digit day this summer with a high of 101. The high drops to 90 on Saturday, 84 on Sunday, and 85 on Monday.