BTS DATA COMPLETE THROUGH JUNE 2026HISTORICAL ODDS · NOT LIVE FLIGHT STATUS
DelayOddsKnow the route before you book
SEA→PHL

Seattle, WA (SEA) to Philadelphia, PA (PHL) flight delay odds

80.0% of 1,326 official scheduled SEA-to-PHL flights arrived on time; 10.6% arrived at least 30 minutes late and 1.7% were cancelled during July 2025–June 2026.

Source: U.S. Bureau of Transportation Statistics · Reporting window: July 2025–June 2026 · Updated September 16, 2026

HISTORICAL ROUTE SIGNALGenerally reliable
80.0%arrived on time
10.6%30+ min late
1.7%cancelled
1,326scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late4.5%all scheduled flights
120+ minutes late1.7%all scheduled flights
Diverted0.5%did not reach as scheduled
Average arrival+0.6 mincompleted flights

Which departure time was most reliable for SEA to PHL?

Among qualifying SEA-to-PHL departure window results, Afternoon had the highest on-time rate: 82.8% of 169 flights. Late morning was lowest at 74.2% across 368 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning13181.7%9.9%4.6%
Late morning36874.2%12.5%1.1%
Afternoon16982.8%10.7%0.6%
Night65882.2%9.6%1.7%

Which weekday was most reliable for SEA to PHL?

Among qualifying SEA-to-PHL weekday results, Tuesday had the highest on-time rate: 85.1% of 188 flights. Thursday was lowest at 75.9% across 191 flights.

DayFlightsOn time30+ minCancelled
Monday19379.3%10.9%2.6%
Tuesday18885.1%5.9%0.5%
Wednesday18682.3%9.1%1.6%
Thursday19175.9%13.6%2.6%
Friday19276.6%16.1%2.1%
Saturday18383.6%6.0%0.5%
Sunday19377.7%11.9%1.6%

Which airline was most reliable for SEA to PHL?

Among qualifying SEA-to-PHL airline results, Delta Air Lines had the highest on-time rate: 84.3% of 51 flights. Alaska Airlines was lowest at 78.0% across 656 flights.

AirlineFlightsOn time30+ minCancelled
Alaska Airlines65678.0%11.7%1.4%
American Airlines61981.7%9.2%2.1%
Delta Air Lines5184.3%11.8%0.0%

Which month was most reliable for SEA to PHL?

Among qualifying SEA-to-PHL month results, April 2026 had the highest on-time rate: 93.9% of 114 flights. July 2025 was lowest at 62.6% across 123 flights.

MonthFlightsOn time30+ minCancelled
July 202512362.6%22.8%4.9%
August 202513671.3%15.4%0.7%
September 202512179.3%9.9%0.0%
October 202512385.4%7.3%1.6%
November 20258783.9%9.2%0.0%
December 20259379.6%10.8%1.1%
January 20266773.1%9.0%6.0%
February 20265583.6%1.8%3.6%
March 20267681.6%11.8%2.6%
April 202611493.9%3.5%0.0%
May 202615881.6%11.4%0.0%
June 202617384.4%8.1%2.3%

What drove SEA to PHL delay minutes?

Late aircraft was the largest recorded SEA-to-PHL delay category, accounting for 41.8% of 14,521 BTS-attributed delay minutes during July 2025–June 2026.

Airline30.4%
Late aircraft41.8%
National airspace15.1%
Weather12.6%
Security0.1%
This is historical evidence, not a forecast.

Weather, schedules and operations change. For a trip you have already booked, use the airline or airport for live status.