If you’re flying out of San Francisco International this summer, you’ve already felt the pain. One in three SFO flights arrived late in June 2026. Delays surged 60% this spring, and the worst part? It’s not just summer storms. Runway construction, new air traffic procedures, and United Airlines’ aggressive growth are all colliding at once. Here’s exactly what’s happening, when you should absolutely not book a departure, and how United plans to fix the mess.
Photo by The Numbers: Just How Bad Is It?
Let’s get specific. In June 2026, SFO saw a 60% increase in delays compared to the same period last year. Average departure delays hit 47 minutes, and some afternoon windows saw delays exceeding 90 minutes. The FAA data shows that between 2:00 PM and 6:00 PM Pacific, the on-time performance dropped to just 62%. That means nearly 4 out of 10 flights are leaving late during that window.
The main culprits? A major runway repaving project that started in March 2026, combined with a new air traffic control sequencing system that hasn’t quite found its rhythm. On top of that, United Airlines added 20% more flying out of SFO in 2025 as part of a long-term growth strategy, and that extra traffic is squeezing an already strained airport.
| Time Window | On-Time Performance | Average Delay | Primary Cause |
|---|---|---|---|
| 6:00 AM – 9:00 AM | 84% | 22 minutes | Morning bank rush |
| 10:00 AM – 1:00 PM | 76% | 31 minutes | Runway construction |
| 2:00 PM – 6:00 PM | 62% | 47 minutes | Winds + construction + traffic |
| 7:00 PM – 10:00 PM | 71% | 38 minutes | Crew timing issues |
Best time to fly: Early morning. Book the first departure of the day (6:00 AM – 7:00 AM) if you can stomach it. The worst slot is 3:00 PM. Avoid it like the plague.
Why the Runway Repaving Is Making Everything Worse
SFO is repaving both of its primary runways in phases this year. The project, which started in March, reduces the number of arrivals and departures per hour from 60 to roughly 45 during construction windows. That’s a 25% capacity cut. The airport says the work is necessary—the runways were last fully repaved in 2007—but the timing is brutal.
Here’s the kicker: the construction schedule runs through November 2026. That means no relief until Thanksgiving at the earliest. If you have a trip planned for August, September, or October, you are flying into a bottleneck.
The FAA has tried to mitigate this by implementing a new ground delay program that holds planes at their origin airports before they even take off for SFO. That’s why you might see a “delayed due to air traffic” message while sitting on the tarmac in Denver. Your plane is being held because SFO literally cannot accept it yet.
United Airlines’ Plan: More Flights, Same Runways
United is the dominant carrier at SFO, controlling roughly 45% of the traffic. In 2025, they announced a 20% increase in flying out of SFO as part of their long-term strategy to make the airport a major transpacific hub. That means more planes packed into the same limited runway slots.
United’s fix plan, announced in late June 2026, has three parts:
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Schedule Smoothing: United is shifting some of its peak-hour departures to earlier or later time slots. They’re moving roughly 15% of their 2:00 PM – 5:00 PM departures to either before 9:00 AM or after 7:00 PM. This should reduce the afternoon pileup by about 12%.
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Aircraft Reassignment: They’re swapping some smaller regional jets for larger widebody aircraft on key routes. This means fewer total flights moving the same number of passengers. For example, instead of three Embraer 175s to Los Angeles, they’ll run two Boeing 737s. Fewer flights = fewer delays.
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Buffer Padding: United is adding 15-20 minutes of “buffer time” to their published schedules for SFO departures. That sounds like a gimmick, but it actually helps. If a flight is scheduled for 3:00 PM but the crew knows they have a 20-minute buffer, they’re less likely to be marked “delayed” when the inevitable 15-minute hold happens.
Will it work? Partially. The buffer padding will improve on-time statistics on paper, but it won’t get you home faster. The schedule smoothing is the real fix, and it won’t fully kick in until September 2026.
Photo by David Syphers on Unsplash
What About American and the Weekend Cuts?
American Airlines quietly announced weekend flight cuts at SFO in early July. They’re reducing Saturday and Sunday frequencies by about 8% through September. Delta is holding steady, but they’re seeing the same delays. This isn’t a United problem—it’s an SFO problem.
The weekend cuts from American suggest they’re expecting the construction delays to persist. If you’re flying American, you might actually see fewer cancellations because they’ve proactively reduced capacity. United, for now, is betting on their smoothing strategy rather than cutting flights.
What You Can Actually Do Right Now
You can’t fix the runway, but you can fix your schedule. Here’s my advice based on flying through SFO four times in the last two months:
Book the first flight of the day. The 6:30 AM United to Denver or the 7:00 AM to Newark. You’ll be at your gate before the construction crews start their morning shift. I flew the 6:45 AM to Chicago last week and was wheels-up at 6:52 AM. The 2:00 PM flight the same day left 55 minutes late.
Avoid connections through SFO if possible. If you live in the Bay Area, you’re stuck. But if you’re connecting from somewhere else, consider routing through LAX or Seattle. Both have better on-time performance right now.
Use the United app to check your aircraft type. If you see a Boeing 737-800 or a 787, you’re on a larger plane that’s less likely to be swapped. If you see an Embraer 175 or a CRJ-900, expect delays, especially in the afternoon.
Sign up for text alerts from your airline. I know it’s obvious, but half the people I see at the gate are surprised by a delay that was announced two hours earlier. United sends them. Turn on notifications.
Consider flying into Oakland (OAK) or San Jose (SJC). Both are running at normal delay rates (around 15-18% late arrivals). If your final destination is the Peninsula or the East Bay, OAK is often faster anyway. I’ve started flying into OAK for work trips to San Francisco proper. The BART ride is 35 minutes from OAK to downtown, versus 25 minutes from SFO. Worth it to skip the delay.
FAQ: Real Questions from Travelers
Q: I have a 3:00 PM flight from SFO next week. Should I change it?
Yes. If you can change without a fee, move it to before 9:00 AM or after 7:00 PM. The 3:00 PM slot is the absolute worst for delays right now. If you’re locked in, arrive at the airport by 1:00 PM so you’re through security before the construction-related ground stops kick in.
Q: Is United compensating passengers for these delays?
United is following standard DOT rules. If the delay is caused by air traffic control or runway construction, they don’t owe compensation. If the delay is due to a maintenance issue or crew timing, you may get meal vouchers or hotel credit. Most of these delays are classified as “air traffic control,” so don’t expect cash.
Q: Will the delays be better in August or September?
No. The runway repaving continues through November. August and September are historically the foggiest months at SFO, which adds another layer of delays. Expect the same or worse until at least October.
Q: Should I book a morning flight even if it’s more expensive?
Yes. The price difference is usually $30-50 for an early morning flight versus midday. That $50 is the cheapest insurance you’ll ever buy against a 90-minute delay. I’ve started booking 6:00 AM flights even when I hate waking up. The math works.
Q: What’s the best airline for avoiding SFO delays right now?
United has the most flights and the most delays—but also the most recovery options. If your United flight is canceled, they have another one in two hours. Alaska Airlines has fewer delays (they fly smaller planes and have less peak-hour traffic) but fewer rebooking options. Delta has the best on-time performance at SFO right now, at 78%, but their schedules are thinner.
The Bottom Line
SFO is in a bad patch. The runway repaving is necessary infrastructure work, but the timing—combined with United’s growth and summer traffic—has created a perfect storm. The good news is that United’s fix plan is real, not just PR. The schedule smoothing and buffer padding will help by September. The bad news is that July and August are going to be rough.
My recommendation: Fly early, fly direct if you can, and consider Oakland as a backup. If you have a tight connection through SFO, change it. You’ll thank yourself when you’re home on time instead of sleeping on a terminal bench.
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Last updated: 2026-07-17