Carrier performance at one airport

UA→SFO

United Airlines at San Francisco International

Departures: 62,048
Period: September 2025 to August 2026
Routes: 25
Rank here: #1 of 8

United Airlines at San Francisco lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 62,048 flights, of which United Airlines flew 62,048 at 79.8% on time.

Measured against the airport rather than the country, United Airlines runs 4 points ahead of the 75.3% weighted average across all carriers at SFO. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

On time

79.8%

61,567 completed departures

Avg delay

58 min

Across delayed flights only

Cancelled

0.46%

At SFO, this carrier only

Rank here

Of 8 carriers clearing the floor at SFO

These figures cover 62,000 flights between September 2025 and August 2026. The median arrival is 6 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Against the competition

Every carrier at SFO, ranked

The choice of carrier is not cosmetic here. United Airlines arrives on time 79.8% of the time; Southwest Airlines manages 54.8%. Sample sizes sit next to every figure, because a two-point gap across 9,968 flights means less than a ten-point one.

On-time performance of all carriers departing SFO
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines (this page)	62,048	79.8%	58 min	0.46%	B+
American Airlines	11,939	76.4%	102 min	1.84%	B
Delta Air Lines	13,973	75.8%	67 min	1.29%	B
JetBlue Airways	4,519	75.6%	76 min	2.21%	B
Alaska Airlines	10,629	75.0%	55 min	1.10%	B
SkyWest Airlines	31,536	73.8%	74 min	1.31%	C
Frontier Airlines	3,581	62.7%	81 min	2.18%	D
Southwest Airlines	9,968	54.8%	61 min	0.90%	F+

The spread between United and Southwest is 25 points, wide enough that it should decide the booking. On a hundred trips that is 25 more arrivals inside the on-time window.

Route by route

Where United Airlines flies from SFO

United Airlines operates 25 routes out of SFO with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

United Airlines routes from SFO
Route	Flights	On time	Avg delay	Cancelled	Grade
SFO to ORD · Chicago	3,885	76.6%	70 min	0.67%	B+
SFO to EWR · Newark	3,861	75.2%	79 min	2.07%	B
SFO to IAH · Houston	3,578	84.0%	50 min	0.25%	B+
SFO to DEN · Denver	3,427	82.1%	58 min	0.18%	B+
SFO to LAX · Los Angeles	3,335	77.7%	46 min	0.15%	B+
SFO to LAS · Las Vegas	2,817	76.8%	55 min	0.35%	B+
SFO to IAD · Washington	2,690	83.0%	58 min	0.63%	B+
SFO to SAN · San Diego	2,666	72.8%	54 min	0.34%	C+
SFO to SEA · Seattle	2,063	75.1%	57 min	0.44%	B+
SFO to BOS · Boston	1,939	78.5%	73 min	1.08%	B
SFO to HNL · Honolulu	1,779	84.5%	63 min	0.11%	B+
SFO to PDX · Portland	1,726	78.8%	62 min	0.12%	B+
SFO to BUR · Burbank	1,663	80.2%	56 min	0.12%	B+
SFO to AUS · Austin	1,637	79.6%	53 min	0.37%	B+
SFO to PHX · Phoenix	1,488	79.9%	59 min	0.40%	B+
SFO to OGG · Kahului	1,313	87.5%	45 min	0.46%	A+
SFO to MCO · Orlando	1,098	86.6%	50 min	0.18%	A+
SFO to SNA · Santa Ana	1,012	82.5%	52 min	0.30%	B+
SFO to ONT · Ontario	987	81.0%	49 min	0.30%	B+
SFO to SBA · Santa Barbara	986	79.9%	55 min	0.51%	B+
SFO to KOA · Kailua-Kona	958	85.7%	50 min	0.52%	A+
SFO to RNO · Reno	944	71.6%	56 min	0.42%	C+
SFO to DFW · Dallas-Fort Worth	916	75.5%	55 min	0.55%	B+
SFO to RDU · Raleigh	885	90.1%	55 min	0.45%	A+
SFO to BNA · Nashville	862	77.0%	59 min	0.46%	B+

Flight by flight

United Airlines flight numbers from SFO

47 United Airlines flight numbers leaving SFO flew their main route often enough to have a record of their own. Grouped by destination.

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 25 points between the best and worst carrier.

5am–8am4,948 flights94.3%
8am–11am16,321 flights82.4%
11am–2pm9,919 flights75.8%
2pm–5pm9,986 flights72.0%
5pm–8pm7,665 flights80.8%
8pm–5am13,209 flights79.4%

Scale runs 65% to 100%.

Book the early departure. Flights leaving between 5am–8am arrive on time 94.3% of the time, against 72.0% for the afternoon window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 16,321 flights scheduled in it.

Across the year

Seasonal pattern

Darker means more delays. Figures are on-time percentages.March best, August worst

August is the worst month at 70.5% on time, 15 points below March, the best at 85.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 5,896 flights.

Delay causes

What holds this operation up

Late-arriving aircraft
48%
Carrier
27%
National Airspace System
24%
Extreme weather
1%

48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 726,000 reported delay minutes here, that single category outweighs weather by 48 to one. The split is drawn from 725,746 reported delay minutes.

Cancellations are rare at 0.46%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

6.2% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

62,048 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 85.4% on time and August 70.5%, a swing of 15 points. If the dates move at all, move them out of August before you think about anything else. 61,567 completed flights over 12 months sit behind that.

Common questions

United Airlines at SFO

How often is United Airlines at SFO delayed?

About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.2% of the 62,048 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on United Airlines at SFO?

United Airlines leads at 79.8% on time across 62,048 flights. Southwest Airlines is at the other end on 54.8%, a gap of 25 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on United Airlines at SFO?

The 5am–8am departure window is the strongest at 94.3% on time. The 2pm–5pm window is the weakest at 72.0%, 22 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are August delays on United Airlines at SFO?

August is the weakest month at 70.5% on time, compared with 85.4% in March. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures