ABC7 News Meteorologist Mike Nicco says extra moisture in the air means more muggy weather.
"You ever wonder what Hawaii feels like? Just step outside today," said Nicco. "We are going to continue to have muggy conditions all day today, so it's going to feel like Hawaii."
The extra humidity is creating more widespread fog in San Francisco and almost everywhere in the Bay Area.
"It's going to be really steamy today, when you start to hit the mid to upper 80s in the South Bay and you throw in the extra humidity -- you're going to be a little hotter than you would normally be," said Nicco.
It will be warmer in parts of the East Bay.
"As you move inland, temperatures will range in the lower to upper 90s," said Nicco. "96 in Brentwood, 95 in Antioch and 94 in Pittsburg and Fairfield."
Nicco's Accuweather forecast shows the humidity will lower tonight, cooler conditions are on the way for better sleeping weather.
"No frizzy Friday, the humid weather will fade out Thursday night around 9 p.m.," said Nicco.
Watch the latest AccuWeather forecast and take a look at recent weather stories and videos.