How Bad Are Flight Delays and Cancellations at SFO?

San Francisco International Airport has developed a reputation among travelers for unpredictable departures and fogbound arrivals, and recent data suggests that perception is largely justified: flights at SFO are more likely to run late than at almost any other major U.S. hub, even as outright cancellations remain comparatively rare.

SFO’s Recent Performance by the Numbers

Publicly available tracking data indicates that over the last 30 days, roughly 37 percent of departing flights from San Francisco International Airport left at least 15 minutes behind schedule, while fewer than 1 percent were canceled. One flight data provider put SFO’s recent cancellation rate at about 0.5 percent, suggesting that most disruptions manifest as delays rather than scrubbed flights.

Longer term federal statistics reinforce this picture. The U.S. Department of Transportation’s Bureau of Transportation Statistics reported that in one recent month, only about 56 percent of arriving flights at SFO were on time, compared with more than 70 percent of departures. That gap highlights how heavily the airport’s performance is influenced by conditions affecting inbound traffic, including weather patterns and congestion elsewhere in the national airspace system.

Separate analyses of multiyear performance for major U.S. airports have also placed SFO near the top of national rankings for delay frequency. One compilation of Department of Transportation data for 2024 identified SFO as having close to 30 percent of flights delayed, the highest share among large U.S. airports in that study, although cancellation rates there remained below some East Coast and Midwest hubs that experience more severe storm disruptions.

Holiday travel periods can magnify those trends. A review of six recent winter holiday seasons using federal on time data ranked SFO among the 10 worst large U.S. airports for delays between mid November and mid January. Even so, the same analysis found that SFO’s holiday performance has shown modest improvement since the depths of the pandemic, with incremental gains in on time operations year over year.

Why Delays at SFO Are So Common

Weather and airfield configuration play outsized roles in SFO’s delay profile. Airport briefings and local meteorological analyses point to the Bay Area’s persistent marine layer and seasonal fog as major contributors to morning and evening slowdowns. When low clouds or poor visibility are present, the Federal Aviation Administration often reduces the arrival rate into SFO and implements ground delay programs, requiring airlines to hold departures from other airports until arrival slots open up.

These ground delay programs can ripple throughout the day. Even if the worst of the fog lifts by late morning, earlier arrival restrictions often leave aircraft and crews out of position, causing subsequent flights to depart late from SFO. Airport communications explain that when only one set of closely spaced runways can be used safely under low visibility procedures, the airport’s arrival capacity drops significantly, which in turn feeds a higher share of delayed operations.

Wind patterns also factor into the disruptions. Recent FAA advisories documented periods when arrival traffic bound for SFO faced average delays approaching one hour because of wind conditions and related spacing requirements between aircraft. In those instances, SFO was already operating with reduced landing capacity due to runway maintenance and updated federal safety rules, further tightening the margin for keeping flights on schedule.

Beyond weather, national air system issues show up prominently in federal breakdowns of delay causes at SFO. Analyses of recent holiday seasons reported that the majority of delays at the airport were linked to systemwide factors such as non extreme weather, air traffic control constraints, high traffic volume and disruptions tied to late arriving aircraft, rather than local staffing shortages or security bottlenecks.

How SFO Compares With Other Major Airports

Compared with other large U.S. hubs, SFO’s cancellation rate is relatively moderate, but its delay rate is high. National comparisons based on Department of Transportation data for 2024 showed SFO leading the country in the share of flights arriving or departing late, while airports such as Newark Liberty in the New York region recorded higher cancellation percentages. In practice, that means SFO travelers are more likely to reach their destinations the same day but often not at the originally scheduled time.

Within California and the West Coast, SFO’s on time performance lags peers such as San Diego, San Jose and Sacramento, all of which typically record higher percentages of punctual arrivals and departures. Those airports experience less chronic fog and benefit from different runway layouts that are less sensitive to small changes in visibility or crosswinds, according to operational comparisons published by aviation authorities.

International benchmarking also highlights SFO’s challenges. A joint performance comparison by the Federal Aviation Administration and European air navigation authorities found that San Francisco trailed many large European hubs and several major U.S. counterparts in arrival punctuality in the early 2020s. While on time performance at SFO has improved somewhat compared with pre pandemic levels, it continues to sit below the national average among continental U.S. airports in the study.

At the same time, overall passenger volumes and traffic mix influence how those statistics are felt by travelers. SFO handles a high share of long haul international and transcontinental flights, which can be more vulnerable to upstream disruptions across multiple time zones. As a result, a single weather event or air traffic issue can cascade into lengthy delays for a wide swath of flights, even if the official cancellation rate remains low.

What Travelers Can Realistically Expect

For passengers planning trips through SFO, the available data paints a picture of an airport where delays are a routine part of the experience, particularly in the morning and during peak travel seasons, but where full cancellations are relatively uncommon. A traveler departing SFO today is more likely than not to encounter at least a modest schedule slip, yet the odds that the flight will be canceled outright remain low compared with several other major U.S. hubs.

Observers who track travel reliability often emphasize that these numbers do not fall evenly across all airlines and routes. Some carriers at SFO, particularly those with large hub operations and more aircraft on the ground, have historically posted better on time performance than smaller competitors that rely on a limited number of daily flights. Analyses of airline punctuality at SFO show that the range between the most and least reliable domestic carriers at the airport can be more than 10 percentage points in on time arrival rates.

Timing also matters. Historical patterns compiled from federal and industry data show that early morning departures from SFO often fare better than afternoon and evening departures, which are more likely to be hit by knock on effects from weather and congestion earlier in the day. Seasonal factors are important as well: late fall and winter holiday periods and the peak of the summer fog season tend to bring higher incidence of delays.

For travelers, the statistics suggest a need for extra buffer time in connections and a flexible mindset rather than an expectation of widespread cancellations or airportwide shutdowns. The numbers show that most flights at San Francisco International eventually take off, but they do so in an operating environment where schedule slippage is common, especially when the coastal weather and complex air traffic picture converge to test the limits of on time performance.