The Bay Area's early October heat is over. By Friday afternoon, temperatures were running 10 to 25 degrees cooler than a day earlier, and as much as 30 degrees cooler in a few spots, according to the National Weather Service's Bay Area office, which summed it up simply: the cool down has arrived.

Friday night: drizzle along the coast

Forecasters said the marine layer was deepening to about 2,000 feet overnight Friday into Saturday morning. That setup gave coastal areas south of the Golden Gate a 20% to 60% chance of measurable drizzle between 8 p.m. Friday and 8 a.m. Saturday.

Saturday: cooler and windy

A mostly dry cold front was forecast to sweep from north to south across the region late Friday and Saturday morning, pushing temperatures 5 to 15 degrees below seasonal averages. Behind it, northwest winds pick up, with afternoon and evening gusts of 35 to 45 mph in gaps, passes and other wind-prone spots. The weather service expected gusts up to about 35 mph (30 knots) at San Francisco International Airport Saturday afternoon. Offshore, gale warnings were posted for waters off the North Bay coast.

In the Santa Clara Valley, the zone forecast called for Saturday highs in the lower 70s, while the coastal North Bay, including Point Reyes, was expected to top out near 60.

Sunday and next week

Winds ease somewhat Sunday, but an even colder air mass settles in, and forecasters said much of the region will struggle to get out of the 60s to low 70s. San Jose's forecast called for highs in the upper 60s Sunday.

From Sunday night into Monday, moisture left over from Tropical Storm Rachel and a cut-off low could bring showers to the north Central Coast. For the Bay Area and North Bay, the chance of rain is put at less than 10% to 15%, though forecasters said that could change depending on the low's track. Cool weather is expected to last into midweek before a gradual warming trend late in the week; San Jose's forecast shows highs back in the 80s by Thursday and Friday.

Fire risk eases

The weather service said the cooler, moister air should bring moderate to excellent humidity recovery inland, easing the elevated fire weather seen earlier in the week. Beach hazards remain in effect along the coast through the weekend, so stay off rocks and jetties.