A large area of high pressure aloft will prevail over the central United States through this weekend. This will result in an extended period of hot weather over central and southeast Illinois, with highs in the 90s each day. A cold front is forecast to move through central and southeast Illinois on Sunday, bringing a return to more seasonable temperatures for Labor Day.
During the heat wave there is a risk for heat-related illnesses, especially for people in poor health or those who have to spend a lot of time exposed to the heat. This includes students who attend schools that lack air conditioning, or are participating in outdoor sports activities.
To avoid being overcome by heat exhaustion or heat stroke, take plenty of breaks in shaded or air conditioned environments, wear light-weight and loose-fitting clothing, and drink plenty of water.
Heat Index Chart
To calculate the Heat Index, find the air temperature on the top of the chart, and then move down the left side for the corresponding relative humidity. For example, a temperature of 90 degreees with a relative humidity of 60% would yield a heat index of 100 degrees.
Keep in mind, temperatures are measured in the shade over a grassy area. For direct sunlight, the heat index can be around 15 degrees hotter.