A Wet Blanket for Summertime : Weather: The clammy, muggy feeling is expected to linger through midweek. However, slightly cooler temperatures are forecast for today and Sunday.

Blame it on Darby.

The hurricane-turned-tropical storm earlier this week blew across the Pacific Ocean near Southern California, leaving a legacy of stifling humidity in Orange County that should last through the weekend.

But conditions should improve by next week, forecasters said Friday.

“By the middle of next week, it looks as if temperatures and humidity will be back to normal,” said Steve Burback, a meteorologist for WeatherData Inc., which provides forecasts for The Times.

High temperatures in Orange County on Friday ranged from 89 in Anaheim to 74 in Newport Beach. Nighttime lows have been unusually warm, Burback noted. The overnight low Friday in Newport Beach was 67 “and that’s quite warm,” he said.

The Orange County forecast for today and Sunday calls for slightly cooler days and nights. High temperatures today should be in the 70s at the beaches and in the mid-80s in inland cities, with overnight lows in the 60s. Sunday’s forecast calls for slightly cooler temperatures.

Humidity, which has been zooming up to 70% in the afternoons in some parts of Orange County, will also be declining slightly over the weekend, according to the WeatherData forecast.

Burback said humidity has been slowly dropping as the remnants of Tropical Storm Darby moved westward, away from California, and farther out into the ocean. But he said the improvement is slow.

“People won’t notice the improvement immediately,” he said. “The change (in humidity) will be gradual. It’ll gradually be more pleasant.”

Darby began Sunday as a hurricane off the shores of Baja California. It gradually diminished to a tropical storm.

The after-effects of Darby included unusual rain over Orange County and continually high moisture in the air. That moisture is what has caused the clammy, muggy feeling so many people have found unpleasant.

Lifeguards in Laguna Beach and Huntington Beach said Friday they’ve noticed one sign of the humidity this week: It’s too uncomfortable for people to lie on the beach very long.

“People definitely have been getting up and going into the water,” said Jeff Kolberg, a lifeguard in Laguna Beach. “It’s been muggy; a very humid feeling.”

Marine Safety Lt. Mike Beuerlein in Huntington Beach said he noticed the same phenomenon. People at the city beach have been going into the water more frequently, he said.

“It’s been very muggy,” said Beuerlein. “There’s been a sticky feeling that won’t go away.”