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DelayAtlas

Carrier route record

UABNA→SFO

United Airlines · Nashville to San Francisco

Flights
862
Period
September 2025 to August 2026
Share of route
73%
Carriers
2
C+GRADE

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.

United on BNA to SFO sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 862 flights, with a median arrival 1 minute early.

The US average over the same twelve months is 77.3%, so there is little to separate United on BNA to SFO from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

74.6%

Arrivals under 15 minutes late, of 852 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.70%

National rate is 1.89%

Whole route

67.9%

Every carrier on BNA to SFO, 1,174 flights

These figures cover 862 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

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Carrier by carrier

United against every carrier on BNA to SFO

United flew 862 of the 1,174 flights on BNA to SFO, most of the route. Its 74.6% on time is 7 points better than the route as a whole, which runs 67.9%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 74.6% to Southwest at 49.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on BNA to SFO
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines (this page)86274.6%58 min0.70%C+
Southwest Airlinesthin sample31249.2%58 min0.64%F+

Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 36 points, against half a point between the best and worst carrier.

  • 5am–8am277 flights87.1%
  • 8am–11am190 flights78.3%
  • 11am–2pm30 flights96.7%
  • 2pm–5pm97 flights63.5%
  • 5pm–8pm268 flights60.9%
  • 8pm–5am—

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.9% on time, against 96.7% for the 11am–2pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 277 flights scheduled in it.

Across the year

United on BNA to SFO through the year

On-time rate by calendar month70J71F82M58A72M60J74J77A93S86O77N75D
Darker means more delays. Figures are on-time percentages.September best, April worst

September is the best month on the calendar at 93.4% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 84 flights.

Across the week, Tuesday is the strongest day at 84.3% on time and Sunday the weakest at 68.6%, a spread of 16 points.

On-time rate by day of the week73.8Mon84.3Tue76.8Wed73.9Thu69.3Fri81.1Sat68.6Sun
Monday: 73.8 percent on time. Tuesday: 84.3 percent on time. Wednesday: 76.8 percent on time. Thursday: 73.9 percent on time. Friday: 69.3 percent on time. Saturday: 81.1 percent on time. Sunday: 68.6 percent on time

Arrival by arrival

How late United on BNA to SFO runs when it is late

The 216 late arrivals split 90 under half an hour, 63 between 30 and 60 minutes, and 63 an hour or more.

  • 15+ min early184 flights21.6%
  • Within 15 min452 flights53.1%
  • 15–29 min late90 flights10.6%
  • 30–59 min late63 flights7.4%
  • 1–2 hours late37 flights4.3%
  • 2+ hours late26 flights3.1%

Scale runs 0% to 100%.

Share of 852 completed flights by arrival against schedule.

50 of 211 late departures made up the time and arrived on time, 24% of them. In the other direction, 55 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.

The worst days

Worst days for United on BNA to SFO

The latest arrival of the period was on 8 April 2026, 5 hours 14 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across April, August and January, with no single month standing out.

The latest arrivals of United on BNA to SFO in the period
DateArrived late byLargest filed cause
8 April 20265 hours 14 minutesCarrier
12 April 20265 hours 7 minutesLate-arriving aircraft
14 August 20264 hours 48 minutesCarrier
5 January 20264 hours 4 minutesNational Airspace System
4 January 20264 hours 1 minuteLate-arriving aircraft

Delay causes

Why United runs late on this route

National Airspace System accounts for 47% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.

  • National Airspace System
    47%
  • Carrier
    30%
  • Late-arriving aircraft
    19%
  • Extreme weather
    4%

47% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 5,939 minutes out of 13,000, against a national NAS share of 21%. The split is drawn from 12,545 reported delay minutes.

Cancellations are rare at 0.70%, 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.

Connections and stage length

What a delay here costs

7.4% 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.

At 1,969 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 77.0% on time across 862 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 862 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking United on BNA to SFO

Put together: treat all of this as provisional. 862 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 74.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 852 completed flights over 12 months sit behind that.

Related

Where to go next

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