Best Time to Fly ONT to SFO
Ontario to San Francisco — month-by-month delay data from the Bureau of Transportation Statistics.
Best month
January
1% on time
Worst month
January
1% on time
ONT → SFO on-time performance by month
24
25
26
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
Better
Monthly breakdown
| Month | On-time | Cancel rate | Flights |
|---|---|---|---|
| January | 1% | 0% | 379 |
| February | 1% | 0% | 366 |
| March | 1% | 0% | 438 |
| April | 1% | 0% | 469 |
| May | 1% | 0% | 464 |
| June | 1% | 0% | 422 |
| July | 1% | 0% | 492 |
| August | 1% | 0% | 369 |
| September | 1% | 0% | 391 |
| October | 1% | 0% | 442 |
| November | 1% | 0% | 432 |
| December | 1% | 0% | 362 |
Frequently asked
What is the best month to fly from ONT to SFO?
January has the highest on-time rate at 1% for flights from Ontario to San Francisco.
What is the worst month to fly ONT to SFO?
January has the lowest on-time rate at 1%, often due to winter weather.
How often are ONT to SFO flights delayed?
On average, 1% of flights from ONT to SFO arrive on time. That means about 99% experience some form of delay.
Source: Bureau of Transportation Statistics.