Forecasters are warning of scorching heat across a wide stretch of the U.S. South and Midwest, where the heat index will feel as high as 117 degrees (47 Celsius) in some spots.
Heat advisories are issued when the heat index reaches 105 degrees, but National Weather Service meteorologist Trisha Palmer said Monday that caution is needed even when the index doesn't quite reach that level.
Some of the most oppressive conditions were in Louisiana, Arkansas, Mississippi and Oklahoma.
The unsafe heat will continue Tuesday with yet another day of 100-degree temperatures expected.
IMPACTS.Dangerously high temperatures and humidity could quickly cause heat stress or heat stroke if precautions are not taken. Tuesday will be the hottest day so far this year with a high of 103 and the heat index will exceed 110.
The difference between an Excessive Heat Warning and a Heat Advisory is how high the heat index gets; the combination of hot temperatures and high dewpoints (70s) will make the heat index climb as high as 110ºF to 115ºF on Tuesday.
"If you're going out in the summer, prepare for the worst", he said.
If required to work outside, NWS said wearing light-weight, loose-fitting clothing, drinking water and taking frequent breaks would all help combat the heat, as would rescheduling outdoor work to the early morning or evening. The number of days would increase to 57 in Baton Rouge; 52 in Jackson; and 50 in Tallahassee.
Perseid Meteor Show Peaks Tonight
According to AMS, the shower will be at its strongest intensity during the Monday night, into the early hours of Tuesday. Perseids are named after the son of Perseus from the Greek mythology as they hail from the constellation of Perseus.