Mercury rises, so does energy use

Probably not a big surprise, but when the thermometer goes up, so does energy use.

Our record early June heat (as seen in the colorful computer model image from the UW on the right), sent the mercury up and also electric demand, too.

PSE's peak energy use the last few days has been about 2,900 megawatts (MW) -- not too far off our all-time peak of nearly 3,200 MW from July 11, 2007. That day was even hotter -- a record 98 degrees at SeaTac.

Our all-time record high for SeaTac is 100 degrees from July 20, 1994.

One other note about these peaks in electric demand, they've all occured around 5 p.m., when people are getting home and when the maximum temperature is typically reached on a hot day.

The sun may be at its zenith closer to noon, but hottest temperatures in our latitude are later in the day, usually between 4 to 6 p.m. depending on variables such as winds, late day clouds and other quirks.

In a typical summer, the Puget Sound area will see 90 degree temperatures once or twice -- with some summers failing to see 90 degrees at all.

The hottest spot in our area? Usually it's from Olympia and south, due to a bit less wind off of Puget Sound than some other areas.

Thinking of air-conditioning? Consider an efficient heat pump.