The fifteen competitors were seen off by a crowd estimated to include 75,000 to 100,000 persons on August 16, 1927. Weather was predicted to have a high fog on takeoff (extending from approximately offshore) and intermittent, localized showers along the route. A fog bank started at the Golden Gate and the entire route was overcast. At Oakland Municipal Airport, clearance to depart was not granted until just before noon; the fog that had lain over the airport did not lift until 10:40 AM.