Will summer runway closures at San Francisco Airport cause delays?

San Francisco International Airport (SFO) temporarily shut two of its four runways in May to perform federally mandated safety upgrades. The runways are scheduled to remain closed until September.

What this means for fliers in and out of the Bay Area depends on whom you ask.

SFO says in a statement that it anticipates “minor delays” during peak times between 9 a.m. and noon, if there’s no fog or other weather delays. Airport spokesman Doug Yakel defines “minor” as about 15 minutes.

Others are less optimistic.

Travel blogger Johnny Jet, a.k.a. John DiScala, recently placed the airport on his “avoid if you can” list.

Business travel writer Joe Brancatelli had this to say in the Business Journals: “The airport insists that the shutdown won’t seriously delay flights, but that claim is incredulous. SFO is one of the nation’s most chronically delayed airports even when all four runways are operating.”

Both suggest flying to Oakland or San Jose as a workaround.

Even before the temporary runway closures, SFO’s ontime performance from May 2013 to April 2014 was 75% for departures and 70% for arrivals, according to U.S. Department of Transportation figures. And delays in the past three months were greater than 50 minutes.

But other factors can account for passengers having to cool their heels. For example, FlightStats between noon and 3 p.m. Monday showed that 60% of flights departed on time, 55% arrived on time. Yakel says by email that this had nothing to do with the runway closures; the delays were caused by Federal Aviation Administration-issued temporary stops because of low clouds and fog.

So where does all this leave travelers? It’s unclear what’s going to happen. Two people think delays inevitable, the airport says they’ll be slight. But really, when you get down to it, what’s another 15 minutes?