The National Weather Service in Paducah has extended an Extreme Heat Warning through 7 p.m. Tuesday for much of southern Illinois, including the Fairfield area.
Forecasters say dangerously hot conditions will continue, with heat index values reaching up to 115 degrees, and some locations could experience even higher values.
The warning remains in effect for all of southeast Missouri and neighboring portions of southern Illinois and far western Kentucky. The warning area includes locations along and west of a line from Fairfield, Illinois, to Cadiz, Kentucky.
Officials warn that the combination of extreme heat and high humidity will significantly increase the risk of heat-related illnesses.
Residents are encouraged to drink plenty of fluids, stay in air-conditioned buildings whenever possible, avoid prolonged sun exposure, and check on elderly relatives, neighbors, and others who may be vulnerable to the heat, including pets.
Anyone who must work or spend time outdoors should wear lightweight, loose-fitting clothing, schedule strenuous activities during the early morning or evening hours, and take frequent breaks in shaded or air-conditioned areas.
The National Weather Service also reminds the public to recognize the signs of heat exhaustion and heat stroke. Anyone suffering from heat stroke should be moved to a cool location immediately, and 911 should be called, as heat stroke is a life-threatening emergency.