Heat gives a jolt to electric bills

June and July constituted the second-warmest such period in Philadelphia since recordkeeping began in 1874, and the latest power numbers indicate how widespread this summer's heat has been.

Power use in June and July was up 16 percent over last year in the 13 states in the PJM Interconnection, and set all-time records in both months.

Granted, people are using more electricity these days when air-conditioning is all but ubiquitous, but still that's impressive.

The 63.2 megawatts used in June were sufficient to power Switzerland for a year, according to PJM. No comparable metaphor was available for July, at 71.8 megawatts.

About 51 million customers are in the 13 states, which include Pennsylvania, New Jersey, Delaware and Maryland. And, yes, it was hot all over.

Philadelphia had an average temperature of 80.0 in the two-month period. The average daily high in July was 90.9, the fourth-highest ever.

It now appears likely that the meteorological summer of 2010 -- defined as the June 1-Aug. 31 period -- will set a record handily for the warmest on record.