Clouds, Even Drizzle, Seen for Weekend : Weather: Thick marine layer keeps temperatures more than 10 degrees cooler than normal and produces odd July rain. It may clear up by Tuesday.

Scattered rainfall dampened Orange County on Friday, but don’t be surprised if you missed it. The drizzle barely amounted to one-hundredth of an inch, forecasters said.

Chances are that the slight drizzle will continue through today.

The unusual July rain has been accompanied by odd temperatures. Orange County has been more than 10 degrees cooler than normal because of a 4,000-foot-thick marine layer that has been hovering for the last few days.

Santa Ana, for instance, posted a high of 73 degrees Friday, in contrast with a normal high of 84. Newport Beach reached just 66 degrees, and San Juan Capistrano hit 75.

Friday’s high of 71 degrees at Los Angeles International Airport was the coolest for a July 19 since record keeping began in 1877, according to forecasters.

Expect these unseasonably low temperatures to continue through the weekend into the early part of next week, forecasters said.

Highs should continue to range from the upper 60s to the low 70s. Lows at night will span the upper 50s to the upper 60s.

“I would say it’s very unusual that it’s taking so long for this to clear up,” said Steve Burback, a meteorologist for the WeatherData, which prepares forecasts for The Times. “I don’t recall seeing the low clouds like this day after day.”

Low clouds and fog are expected to continue Saturday morning along the Southern California coast, the National Weather Service said.

Burback predicted some clearing by Tuesday or Wednesday.

The reason for the cool weather is that the clouds are so thick, the sun’s rays can’t penetrate them to warm the atmosphere.

“The sun just burns off the top of the cloud cover, because it can’t get through,” Burback said. “It’s a real thick layer, and the winds keep feeding it with more cool air from over the coastal waters.”

Staff writer John H. Lee contributed to this report.