The National Weather Service has issued an Extreme Heat Warning for the St. Louis Metro Area from Noon Saturday 6.21.25 to 9:00 pm Tuesday 6.24.25. Dangerously hot conditions with heat index values up to 108+ expected. From Weather.Gov -- An Extreme Heat Warning is issued when extremely dangerous heat conditions are expected or occurring. Avoid outdoor activities, especially during the heat of the day. If you must be outside, be sure to drink plenty of water and take frequent breaks in the shade. Stay indoors in an air-conditioned space as much as possible, including overnight. Check on family, neighbors, elderly, and pets.