Overview

• National Weather Service forecasts daytime heat indices climbing as high as 108–116°F across the Southeast coast and upper Midwest through midweek.
• Overnight and early morning lows are expected to hover in the 70s, providing minimal cooling relief across most affected regions.
• PJM Interconnection and other grid operators have issued hot weather alerts to prepare for record air-conditioning demand stressing electricity networks.
• High humidity and sustained extreme temperatures elevate the risk of heat-related illnesses, building on a pattern that has claimed over 14,000 lives in the past four decades.
• A cold front is projected to arrive Wednesday evening, ushering in cooler temperatures and lower humidity by Thursday and Friday.