(CNN) The South was sweating through Memorial Day with temperatures hotter than an average summer day.

The region has been under a heat dome since Friday. That's when high pressure aloft acts like a lid trapping the heat below, setting the stage for potentially life-threatening conditions.

Some locations, such as Columbia, South Carolina and Augusta, Georgia, broke triple-digit temperature records Monday.

Highs will be around 100° today. The daily record for both Columbia and Augusta is 99°. Drink plenty of water during your #MemorialDay activities! pic.twitter.com/KZ71zYIH3u — NWS Columbia (@NWSColumbia) May 27, 2019

Gainesville, Florida hit 100 degrees, tying its 1953 record while Fayetteville, North Carolina beat its 1926 record by four degrees, also reaching 100.

Three cities in Georgia also saw record-breaking heat.

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