Spot wholesale electricity along the U.S. Mid-Atlantic region increased on higher than forecast demand.

On-peak power at PJM Interconnection LLC’s benchmark western hub, which serves Washington, was at 85,315 megawatts at 2:40 p.m. New York time, exceeding the grid operator’s forecast of 85,034 megawatts, according to data on its website. Temperatures in the nation’s capital reached 71 degrees Fahrenheit (22 Celsius), 3 degrees above average, according to AccuWeather Inc., in State College, Pennsylvania.

Spot power at PJM’s Western hub rose $16.48, or 47 percent, to $51.21 a megawatt hour in the hour ended at 2 p.m. New York time from the same time April 18, data compiled by Bloomberg show.

Prices in New York rose $13.90, or 32 percent, to $58.02 at 2 p.m. The temperature reached 67 degrees at 2 p.m., matching the day’s average high.

Power in Boston and Northeast Massachusetts fell $4.20, or 11 percent, to $33.01. On-peak power in New York was $77.09 less than power in Boston, compared with 72 cents higher on April 18.

To contact the reporter on this story: Mario Parker in Chicago at mparker22@bloomberg.net To contact the editors responsible for this story: Bill Banker at bbanker@bloomberg.net Richard Stubbe