Fleet week's Air Show happens next Friday, Saturday and Sunday. An estimated 1.5 million people are expected for the events.
The Oracle Open World conference kicked off Sunday and runs through this week. Howard Street between 3rd and 4th is closed for the event.
"This is an amazing event. 60,000 people are in San Francisco, welcome to Open World, " said San Francisco Mayor Ed Lee.
The Hardly Strictly Bluegrass Festival happens next weekend in Golden Gate Park.
Police say drivers can expect long delays around the city. Take public transportation if you can. If you must bring your car, pack your patience.