An extreme heat warning will be in effect until 9 p.m. today as the National Weather Service predicts temperatures in Iron Mountain could reach 100 degrees.

The record-high temperature at Iron Mountain-Kingsford for July 13 is 103 degrees, set in 1936. The all-time highest July temperature is 104 degrees set in 1917.

There have been record highs of 100 degrees or better on 10 different dates in July, but none since 2006, NWS records show.

Heat-related illnesses increase significantly during extreme heat and high humidity events, the NWS advised.

“Take extra precautions when outside,” forecasters said. “Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.”

Tonight’s predicted low is 75 degrees. The forecast calls for a high of 98 on Tuesday and 90 on Wednesday.

Sunday’s unofficial high at Iron Mountain was 91 degrees, with a heat index into the 100s.

Severe thunderstorms were reported in the Escanaba and Marinette, Wis., areas late Sunday afternoon, moving south.