According to Bloomberg, electricity prices in New England tripled on Monday from a year ago. Since the weekend, a heat wave blanketed the Mid-Atlantic and Northeast but will subside by midweek. 

Gary Cunningham, director of market research at Tradition Energy, said energy demands are way "above normal" for this time of year because of increasing air-conditioning use. New England's grid operator could reach its summer peak in June instead of August, typically the hottest part of summer.

Monday's highs were 90-95 degrees in the Baltimore–Washington metropolitan area to New York City to Boston. 

Grid operator PJM Interconnection LLC, a regional transmission organization serving all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and the District of Columbia, issued a hot weather alert Monday. PJM requested owners of transmission lines and power plants to delay maintenance. 

On-peak electricity prices for Bloomingdale, Massachusetts, energy prices per megawatt-hour spiked on Saturday, Sunday, and Monday. 

Peak energy prices for New York City also spiked. 

The heat wave is expected to dissipate by mid-week as Mid-Atlantic and Northeast temperatures will be around average or slightly below normal as a cold front rolls in through the weekend.