FlightRecord

San Francisco (SFO) to Houston (IAH): On-Time Performance

Data through May 2026

San Francisco (SFO) to Houston (IAH) effectively runs on two schedules. In September 2025, 92% of arrivals were on time; in December 2024 that fell to 72% — a 21-point seasonal swing. Across the full period the route averages 84% on-time against a national 78%.

On-time
84%
arrived <15 min late
Avg delay
10 min
completed flights
Cancelled
0.7%
Flights/day
9.9
last 12 months
Duration
3h 54m
scheduled
Distance
1,635 mi

Monthly on-time trend

Monthly on-time percentage for SFO to IAH flights50%75%100%June 2024: 82% on-time (270 flights)82Jun 2024July 2024: 77% on-time (279 flights)77August 2024: 85% on-time (280 flights)85September 2024: 92% on-time (270 flights)92Sep 2024October 2024: 90% on-time (279 flights)90November 2024: 82% on-time (268 flights)82December 2024: 72% on-time (282 flights)72Dec 2024January 2025: 82% on-time (238 flights)82February 2025: 90% on-time (229 flights)90March 2025: 85% on-time (284 flights)85Mar 2025April 2025: 91% on-time (291 flights)91May 2025: 87% on-time (303 flights)87June 2025: 77% on-time (296 flights)77Jun 2025July 2025: 81% on-time (299 flights)81August 2025: 79% on-time (299 flights)79September 2025: 92% on-time (289 flights)92Sep 2025October 2025: 90% on-time (306 flights)90November 2025: 81% on-time (299 flights)81December 2025: 84% on-time (311 flights)84Dec 2025January 2026: 86% on-time (303 flights)86February 2026: 87% on-time (277 flights)87March 2026: 87% on-time (310 flights)87Mar 2026April 2026: 88% on-time (300 flights)88May 2026: 79% on-time (307 flights)79

Best time to fly from SFO to IAH

Aim for departures around 5 a.m. (96% on-time); avoid 11 a.m. departures (72%).

On-time percentage by scheduled departure hour, SFO to IAH5 a.m.: 96% on-time (726 flights)57 a.m.: 94% on-time (730 flights)78 a.m.: 87% on-time (167 flights)89 a.m.: 82% on-time (563 flights)910 a.m.: 73% on-time (241 flights)1011 a.m.: 72% on-time (489 flights)1112 p.m.: 75% on-time (190 flights)121 p.m.: 77% on-time (543 flights)132 p.m.: 83% on-time (720 flights)144 p.m.: 83% on-time (451 flights)165 p.m.: 81% on-time (21 flights)176 p.m.: 81% on-time (425 flights)187 p.m.: 88% on-time (203 flights)1911 p.m.: 85% on-time (731 flights)23scheduled departure hour

By day of week

DayOn-timeAvg delay
Monday83%11 min
Tuesday87%7 min
Wednesdaybest87%7 min
Thursday84%10 min
Friday82%11 min
Saturday83%11 min
Sunday83%11 min

What causes delays on this route

Share of total delay minutes by cause, as reported by carriers to the US DOT.

  • Late-arriving aircraft37%
  • Airline operations37%
  • National airspace system25%
  • Weather1%

Frequently asked questions

How often are flights from SFO to IAH delayed?
16% of SFO–IAH flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 10 minutes.
What is the best time of day to fly from SFO to IAH?
Departures around 5 a.m. have the best record (96% on-time), while departures around 11 a.m. have the worst (72%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
How long is the flight from SFO to IAH?
The scheduled SFO–IAH flight time averages 3h 54m over 1,635 miles. Actual arrival times vary — flights on this route land 15+ minutes late 16% of the time.
How often are SFO to IAH flights cancelled?
0.7% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
What is the worst month to fly from SFO to IAH?
December 2024 was the roughest month in this dataset, with only 72% of arrivals on time. The best was September 2025 at 92%. If your dates are flexible, that 21-point gap is worth planning around.

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Based on 6,869 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.