Route Reliability
Ontario → Seattle
ONT–SEA · 956 miles · Ontario International Airport to Seattle–Tacoma International Airport
- 87%
- Arrive within 15 minutes
- 1 min early
- Average arrival delay
- 1.2%
- Cancelled
- 2,577
- Flights in the data
Data through May 2026.
Who flies it best
Ranked by on-time arrivals. Historical results, not predictions.
- 1.Delta Air Lines92%1,141 flights
- 2.Frontier Airlines84%171 flights
- 3.Alaska Airlines83%1,265 flights
What the data says
Morning-you made the right choice.
ONT–SEA flights departing between 6–9 AM arrived on time 94% of the time, versus 66% between 6–9 PM.
Wednesday has been the better bet.
A small edge: 90% on time on Wednesdays against 83% on Fridays.
Delta Air Lines runs this route best.
Delta Air Lines arrived on time 92% of the time on this route; Alaska Airlines managed 83%.
Best historical flights
Ranked by on-time arrivals, minimum 100 flights. Past performance, not a promise.
Top flights by on-time rate
More flights on this route
The breakdown
- Mon87%(386 flights)
- Tue89%(355 flights)
- Wed90%(343 flights)
- Thu85%(367 flights)
- Fri83%(372 flights)
- Sat88%(324 flights)
- Sun88%(397 flights)
- 3–6 AM—(2 flights)
- 6–9 AM94%(737 flights)
- 9 AM–12 PM92%(567 flights)
- 12–3 PM80%(316 flights)
- 3–6 PM88%(653 flights)
- 6–9 PM66%(269 flights)
Jun 86% → May 90% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 86% | 265 |
| July 2025 | 83% | 293 |
| August 2025 | 85% | 264 |
| September 2025 | 89% | 211 |
| October 2025 | 85% | 198 |
| November 2025 | 87% | 204 |
| December 2025 | 83% | 197 |
| January 2026 | 88% | 157 |
| February 2026 | 96% | 135 |
| March 2026 | 88% | 174 |
| April 2026 | 91% | 199 |
| May 2026 | 90% | 247 |
Same trip, other airports
Keep nerding
Based on 2,577 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.