The fog rolling in off San Francisco Bay is as familiar to visitors as the city’s iconic cable cars, and it also plays a major role in flight delays at the city’s airport.

The Dallas Morning News reports that more flights are delayed at San Francisco International than any other US airport, often because of low clouds and fog.

Fog generally isn’t the issue at Newark International Airport, but travellers from the metropolitan New York airport have a two-in-three chance of being delayed due to weather, according to a report from the Weather Channel. Snow causes many of the problems at Chicago O’Hare International Airport, the third-worst US airport for weather delays and cancellations, while New York’s LaGuardia International Airport is bedeviled by all manner of bad weather — rain, snow, fog, wind, and thunderstorms.

Other US airports where weather delays are common include Denver International Airport, Philadelphia International Airport, Boston Logan International Airport, George Bush Intercontinental Airport in Houston, New York’s JFK Airport, and Atlanta Hartsfield-Jackson International Airport.