Hot weather updates: Week of June 29, 2026

June 30, 2026 — 11:00 a.m.

ISO New England is closely monitoring system conditions as hot, humid weather is expected to drive high electricity demand across the region over the coming days.

At this time, ISO-NE expects the regional power system will have sufficient resources to meet anticipated demand. While this predicted demand would be the highest so far this year, the projections are in line with the ISO’s forecasts for the summer.

Forecasters are indicating temperatures will reach the upper 90s to low 100s later this week in parts of southern New England, including Boston and Hartford, the region’s two largest centers of electricity demand. Hot weather is expected to continue through the holiday weekend.

During periods of high electricity demand, consumers can help reduce the amount of power needed by being mindful of their energy use during the peak-use hours of 4 to 8 p.m.

As of Tuesday morning, the ISO is forecasting the following peak electric loads:

Wednesday, July 1: 23,950 MW

Thursday, July 2: 25,850MW

Friday, July 3: 24,000 MW

Saturday, July 4: 21,950 MW

Peak demand is the time when electricity use is expected to be highest. For additional context, 1 megawatt (MW) of electricity can serve about 750 to 1,000 average homes in New England.

ISO New England’s system operators monitor grid conditions around the clock and are well-trained to handle increased seasonal demand, unexpected generation loss, or transmission outages. The ISO has a range of tools and procedures available to mitigate concerns if system conditions change. For more detailed information, visit the Seven-Day Capacity Forecast page.