REGION: Summer breeze makes us feel fine

Mild weather gives air conditioners a breather, but smog refuses to take vacation

By DAVE DOWNEY - Staff Writer | Thursday, August 21, 2008 5:51 PM PDT ∞

It hasn't exactly been chilly, but the summer of 2008 has been a breeze so far for much of Southern California.

While the season roared in on a scorching weeklong heat wave in June, temperatures quickly backed off and stayed on the mild side.

"The marine layer came back with a vengeance in much of July and August," said Dan Atkin, a meteorologist at the National Weather Service office in Rancho Bernardo.

"Almost every day, we've had low clouds and fog in the coastal areas. And we've had a good onshore flow, which has been keeping temperatures west of the mountains ---- where most people live ---- at or below seasonal temperatures."

As a result, coastal sun seekers have been donning sweat shirts on persistently gray mornings. Inland dwellers have been throwing open windows to invite night breezes into their homes and marveling at pleasant walks in the park.

The weather has cooled the usual soaring demand for power to drive air conditioners at this time of year. But it hasn't delivered clean air. Nor has the temperature tamed the demand for recreation at the region's cool spots: the beach and the mountains.

The temperature in July was 5 degrees below normal in Escondido, 3 degrees below normal in Oceanside and a half-degree below normal in Temecula ---- and way below the numbers recorded during the sweltering summer of 2006, Atkin said.

A warm-up is in the forecast, but it is only expected to drive temperatures up to seasonal averages, according to the National Weather Service. Temperatures are forecast to top off by Tuesday at 92 in Temecula, 85 in Escondido and 74 in Oceanside.

The milder weather has been tamping down demand for electricity. Despite the growing populations within their service areas, San Diego Gas & Electric Co. and Southern California Edison report that customers used about the same amount of electricity in July and August as in the same months last year.

Stephanie Donovan, a spokeswoman for SDG&E, said its peak demand reached 4,149 megawatts on June 20, well below the all-time peak of 4,646 megawatts set last year on Labor Day weekend.

"It's been warm," Atkin said, "but it hasn't been so hot that we've had to run the air conditioner all day and night like in other years."

While the milder weather has saved electricity, it hasn't delivered cleaner air.

Bill Brick, senior meteorologist for the San Diego County Air Pollution Control District, said the San Diego region has recorded twice as many bad air days this year, 30, as it did in 2007 by this time. But Brick said that is primarily due to unseasonably warm weather in spring and early summer, and the drifting smoke from distant wildfires.

Smog readings have exceeded federal limits on 12 occasions in Escondido and two in Oceanside, compared to none this time last year, he said.

Joe Cassmassi, a meteorologist with the South Coast Air Quality Management District, which monitors air quality in Riverside, Orange, Los Angeles and San Bernardino counties, said there have been 57 bad air days recorded so far at the Lake Elsinore station compared with 32 one year ago.

Temperature is a major factor in the number of smog, or ozone, violations in any given year. Ozone forms when gases belched out of car tailpipes hover in stagnant summer air and cook in the hot sun. Once temperatures reach the 90s, as they do even on a mild summer day inland, conditions are ripe for ozone to form, Cassmassi said.

As well, the milder weather hasn't translated into thinner crowds at the region's favorite summer playground.

"We're still seeing big crowds at the beach," said Greg Uruburu, Solana Beach lifeguard supervisor.

The crowds continued to flock to the sand even though temperatures averaged just 69.5 degrees at Oceanside Harbor in July, below the normal high of 72.1, said Stefanie Sullivan, a National Weather Service meteorologist. The average for August so far has been a little higher, at 71.8 degrees, but still well below the historical average of 73.6 degrees.

In Escondido, the highs of 82.6 degrees in July and 85.4 degrees in August are under historical averages of 87.7 and 88.2, respectively, Atkin said.

In Temecula, the temperature averaged 90.6 degrees in July, slightly below the long-term average of 90.9 degrees, he said. So far in August, the Wine Country community is bucking the regional trend, averaging 93.3 degrees ---- a little more than the seasonal norm of 91.8.

Contact staff writer Dave Downey at (760) 745-6611, Ext. 2623, or ddowney@nctimes.com.