84% of flights from San Francisco to Houston arrived on time over the past 12 months. That is better than the typical U.S. route. The 5 a.m. departures ran on time 96% of the time; the 10 a.m. ones 63%. 4% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SFO → IAH: when a flight was late, it was under 45 minutes late 70% of the time. About 1 in 29 flights landed an hour or more late, and 1 in 179 three hours or more; 0.3% were cancelled outright.
- On time or early84%
- 15–30 min late7.7%
- 30–60 min late4.8%
- 1–2 hours late2.1%
- 2–3 hours late0.8%
- 3+ hours late0.6%
- Diverted0.2%
- Cancelled0.3%
Share of all 3,578 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| United Airlines | 3,578 | 84% | 0.3% | −7 min | 3.4% | +50 min | United Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at SFO). Delays build through the day as late planes knock on, so early flights usually do best.
Last flight of the day
On SFO → IAH, each airline's last flight of the day was cancelled 0.3% of the time, against 0.3% for its earlier flights, about the same. It arrived 3+ hours late 1.1% of the time (earlier flights: 0.5%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| United Airlines | 11:59 p.m. | 0.3% | 1.1% | 0.3% | first flight 12:45 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
By month
Each calendar month pooled over 2023–2026. Best: September (90%). Worst: July (77%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 527 | 80% | 0.2% |
| Tuesday | 499 | 85% | 0.2% |
| Wednesday | 510 | 87% | 0.2% |
| Thursday | 516 | 83% | 0.4% |
| Friday | 508 | 83% | 0.2% |
| Saturday | 501 | 84% | 0.2% |
| Sunday | 517 | 83% | 0.4% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 5 · airline 4
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| UA 604 | 12:45 a.m. | 156 | 81% | 0.0% | −5 min | United Airlines |
| UA 2168 | 5:00 a.m. | 159 | 95% | 1.3% | −10 min | United Airlines |
| UA 686 | 7:05 a.m. | 180 | 94% | 0.6% | −13 min | United Airlines |
| UA 2498 | 8:55 a.m. | 121 | 88% | 0.0% | −6 min | United Airlines |
| UA 1387 | 12:15 p.m. | 288 | 75% | 0.4% | +1 min | United Airlines |
| UA 2305 | 4:40 p.m. | 328 | 81% | 0.0% | −6 min | United Airlines |
| UA 505 | 11:59 p.m. | 327 | 82% | 0.3% | −6 min | United Airlines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Mar 16, 2026 | 10 | 20% | 0 |
| Jan 3, 2026 | 10 | 30% | 0 |
| Jul 13, 2026 | 10 | 40% | 0 |
| Nov 5, 2025 | 10 | 40% | 0 |
| Mar 11, 2026 | 10 | 40% | 1 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of San Francisco or Houston. SJC → HOU has been 6 points more reliable.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| SFO → IAH (this route) | 3,578 | 84% | 0.3% |
| SJC → HOU San Jose to Houston Hobby | 365 | 89% | 0.3% |
| OAK → HOU Oakland to Houston Hobby | 376 | 75% | 0.5% |
Questions
How often are flights from SFO to IAH on time?
84% of 3,578 scheduled flights from San Francisco, CA to Houston, TX arrived within 15 minutes of schedule between September 2025 and August 2026. 0.3% were cancelled.
What is the best time of day to fly SFO to IAH?
Flights scheduled to leave at 5 a.m. were the most reliable (96% on time). The 10 a.m. departures were the least (63%).
What month has the most delays from SFO to IAH?
July (77% on time). The best month is September (90%), over 2023–2026.
Is the last flight of the day from SFO to IAH more likely to be cancelled?
Not much. Each airline's last SFO–IAH flight of the day was cancelled 0.3% of the time over the past year, against 0.3% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- IAH → SFO (return)
- San Francisco (SFO) delays by hour
- Flights into Houston Bush Intercontinental (IAH)
- United Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.