It’s 7 a.m. and 51º. The skies are mostly cloudy, but the sun will be coming out later today. Details here.

If you’re a driver, brace yourself (or ditch the car) for tomorrow’s 20th anniversary of Critical Mass, the bicycle movement that challenges America’s reliance on oil, gas and the automobile. Chris Carlsson, spokesman for Critical Mass, says he expects 5,000 to 10,000 riders to clog the city’s streets.

“It’s going to be a gigantic mess,” Carlsson told the San Francisco Chronicle. “But it is going to be fun.” Read more here, and look for our coverage of the event soon.

Is it cheaper to buy in the Bay Area than rent these days? The San Francisco Chronicle investigates. See where our city ranks among others with the largest year-over-year asking rent increases.