The warmest summer in five years is expected to intensify during August, starting this weekend, according to the National Weather Service in San Diego.
August is normally the hottest month of the year anyway, with a normal high of 77.6 at Lindbergh Field, said forecaster Wilbur Shigehara. But, because of an unusual high pressure dome that has been hovering over San Diego instead of northeastern Arizona, temperatures will be 3 or 4 degrees above normal for this time of year if July is any indication.
In July, 24 days were above the normal temperatures for this time of year, Shigehara said. The average monthly temperature was 72.3 degrees, or 2 degrees above normal. The hottest temperature was 85 on July 11 and the lowest was 62 on July 8.
"So, if San Diegans thought we were getting more sunshine than usual, it was hotter than normal and more humid, they were right," he said. Even ocean waters were warmer. At Mission Beach, the water temperature is usually 66.3 in July. All month it was from 69 to 70.
"People have been calling us saying their sinuses are bothering them and blaming it on the weather and asking us for advice," Shigehara said. He was quick to add that forecasters have no medical advice to give out, but that they do sympathize.
The weather will gradually warm today, and temperatures will increase 1 to 2 degrees Saturday and Sunday. The cloud cover that usually keeps temperatures down will decrease each morning.
At the beach, temperatures will range from 71 to 75 today and nudge up to 71 to 77 on the weekend. Sea breezes are blowing at 10 to 16 m.p.h. The water temperature is 71, with surf at 2 to 3 feet.
Although August to mid-September is hurricane season, no storms are brewing in the Pacific to push the surf up, he said.
In the coastal strip, temperatures will range from 76 to 82 Friday, increasing on Saturday to 77 to 84 and up another degree on Sunday. Nighttime lows will dip to 64 to 70. Those temperatures are 1 to 3 degrees above normal, said Shigehara. By next week, temperatures will rise another degree.
In the inland area, highs will range from 82 to 91 today, 84 to 93 Saturday and, by Sunday, 85 to 96. Temperatures tonight will range from 56 to 63, rising a few degrees over the weekend.
As the high pressure dome builds and high-level winds begin to circulate around it, the mountains and deserts should watch for thunderstorms. The winds will bring moisture from Mexico, which, with the winds, increase the possibility of thunderstorms over the weekend, he said.
Mountain temperatures will soar into the high 80s and approach the 90s over the weekend, with night temperatures decreasing to 54 to 63, Shigehara said.
Desert areas will heat up to 108 to 114 today and over the weekend, decreasing only to 75 to 85 at night. People going to the deserts should beware of dehydration and take lots of water, Shigehara said.