Families set up their tents at Sugarloaf State Park campsites Monday while 45 miles to the west — and about 30 degrees cooler — people flew kites and picnicked on packed Sonoma Coast beaches.
The Fourth of July has already begun luring people outside in great numbers, launching the unofficial extended holiday week as temperatures reached near-record highs.
"With the heat wave coinciding with the holiday, we were expecting a lot of visitors," said State Parks Ranger Te Nealy who patrols the Sonoma Coast. "But it's exceeded our expectations so far."
More than 4.7 million Californians plan to get out of town this week, according to AAA Northern California's holiday travel forecast.
Campgrounds are booked across the state. Only 24 of the state's 280 parks had campsites still available Monday. The closest parks with open campsites are in Lake County, including Clear Lake State Park.
Meteorologists kicked up their temperature predictions, making this week's expected extreme temperatures even more sizzling.
Tuesday's Santa Rosa high temperature prediction had been 95 or 96 degrees. But that was revised Monday afternoon to a prediction of 102 degrees, according to AccuWeather.
The National Weather Service has issued an "extreme heat advisory" for most of California and Nevada and parts of Arizona into Wednesday night.
Sonoma County health officials advised people to avoid heat-related medical emergencies by wearing light clothing and taking a trip to an establishment with air conditioning, such as a library.
"Stay cool, drink plenty of fluids," Sonoma County Health Officer Dr. Lynn Silver Chalfin said.
Residents will continue getting a break from the daytime heat at night, with temperatures dipping into the 60s. Later in the week, nighttime lows will reach into the 50s in some areas.
That gives buildings and the body a much needed rest and will help prevent dehydration, Silver Chalfin said.
The greatest daytime relief will be on the coast where Monday's high was 73 degrees in Sea Ranch and 59 in Bodega Bay.
"A lot of people want to beat the heat and come out to the coast," said Supervising State Parks Ranger Jeremy Stinson. "As tempting as it might sound when it's 100 degrees in Santa Rosa, it's not a great place if you want to go swimming."
The treacherous surf hovers around 50 degrees, he said.
Current predictions predict temperatures will drop into the high 90s on Wednesday and could be in the lower 90s for the Fourth of July holiday. Friday could see a drop of about 10 degrees into the 80s. That could hold through the weekend.
It's the result of a large high pressure system handing over the Southwest, where in hot spots in Arizona, Death Valley and Las Vegas temperatures have soared above 120.
More than 3.7 residents will drive to their destinations, AAA estimated, despite rising gas prices with Monday the first day of a 3.5-cent-per-gallon state tax increase.
Gas was an average of $3.945 a gallon in Santa Rosa on Monday, according to the AAA Fuel Gauge Report, 18 cents higher than 2012.
Staff Writer Randi Rossmann contributed to this report. You can reach Staff Writer Julie Johnson at 521-5220 or julie.johnson@pressdemocrat.com. On Twitter @jjpressdem.
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