Best Time to Fly ORD to SAN: On-Time Stats by Hour & Airline
Chicago O'Hare International → San Diego International
Data through July 2026 · Last updated October 18, 2026
3,870 flights were scheduled from Chicago (ORD) to San Diego (SAN) in the last 12 months, and 71.8% of those that flew arrived on time, 5.8 points below the US average of 77.6%.
Among 4 airlines, United Airlines led with 77.6% on time and American Airlines was last with 66.5%.
Over 24 months, Tuesday was the most reliable day (80% on time) and December the worst month (69%).
The cancellation rate was 1.2% (US average 1.8%).
ORD to SAN on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 77.6% | 65 min | 0.4% | 1,673 |
| Alaska Airlines | 68.7% | 72 min | 2.3% | 777 |
| Frontier Airlines | 67.7% | 120 min | 0.0% | 31 |
| American Airlines | 66.5% | 65 min | 1.7% | 1,389 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly ORD to SAN
On-time arrival % by scheduled departure hour (local time), 6,892 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 87.9% | 0.0% | 182 |
| 7am–8am | 89.1% | 0.4% | 702 |
| 8am–9am | 85.0% | 0.6% | 622 |
| 9am–10am | 78.4% | 0.5% | 630 |
| 10am–11am | 75.7% | 0.2% | 488 |
| 11am–12pm | 73.0% | 0.9% | 336 |
| 12pm–1pm | 76.0% | 0.0% | 50 |
| 1pm–2pm | 79.4% | 0.6% | 669 |
| 2pm–3pm | 70.8% | 0.0% | 185 |
| 3pm–4pm | 69.8% | 1.0% | 194 |
| 4pm–5pm | 70.1% | 0.6% | 872 |
| 5pm–6pm | 65.9% | 0.6% | 353 |
| 6pm–7pm | 62.8% | 1.5% | 202 |
| 7pm–8pm | 64.7% | 2.0% | 639 |
| 8pm–9pm | 63.5% | 1.8% | 394 |
| 9pm–10pm | 53.1% | 2.9% | 374 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on ORD to SAN
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 58.9% | -17.7 pts | 6.7% | 120 |
| Christmas & New Year (Dec 20 - Jan 3) | 62.6% | -14.0 pts | 0.7% | 280 |
| Summer peak (Jun 15 - Aug 15) | 67.8% | -8.8 pts | 0.8% | 1,419 |
| All other days | 76.6% | — | 0.8% | 5,073 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).