Heat safety guidelines from the Korey Stringer Institute
The Korey Stringer Institute, named for a Minnesota Vikings player who died of heat stroke in 2001, shares these guidelines for wet bulb globe temperatures in different parts of the U.S.
Table showing different temperatures and recommendations for each.
Category 1 includes most of New England, states bordering Canada, and the Rockies. Category 3 generally includes states south of Pennsylvania, Ohio, Iowa and Kansas plus most of New Mexico, Arizona and California's Central Valley. Category 2 is in between.