Route Reliability
Seattle → Philadelphia
SEA–PHL · 2,379 miles · Seattle–Tacoma International Airport to Philadelphia International Airport
- 81%
- Arrive within 15 minutes
- 1 min
- Average arrival delay
- 1.4%
- Cancelled
- 1,269
- Flights in the data
Data through May 2026.
Who flies it best
Ranked by on-time arrivals. Historical results, not predictions.
- 1.American Airlines84%588 flights
- 2.Alaska Airlines78%656 flights
Not enough history to rank: Delta Air Lines (25 flights). We rank airlines only after 100 flights on the route.
What the data says
The 6–9 AM departure wins.
SEA–PHL flights departing between 6–9 AM arrived on time 87% of the time, versus 73% between 9 AM–12 PM.
Thursday is the weak spot.
SEA–PHL flights arrived on time 85% of the time on Wednesdays. On Thursdays: 76%.
American Airlines has a slight edge here.
American Airlines arrived on time 84% of the time on this route; Alaska Airlines managed 78%.
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
- Mon81%(177 flights)
- Tue84%(173 flights)
- Wed85%(174 flights)
- Thu76%(178 flights)
- Fri77%(182 flights)
- Sat83%(177 flights)
- Sun78%(185 flights)
- 6–9 AM87%(77 flights)
- 9 AM–12 PM73%(358 flights)
- 12–3 PM81%(166 flights)
- 9 PM–12 AM84%(645 flights)
Jun 67% → May 83% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 67% | 116 |
| July 2025 | 67% | 115 |
| August 2025 | 73% | 135 |
| September 2025 | 80% | 120 |
| October 2025 | 88% | 121 |
| November 2025 | 86% | 86 |
| December 2025 | 84% | 92 |
| January 2026 | 78% | 63 |
| February 2026 | 93% | 53 |
| March 2026 | 84% | 74 |
| April 2026 | 94% | 114 |
| May 2026 | 83% | 157 |
Keep nerding
Based on 1,269 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.