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

Seattle, WA (SEA) to Washington, DC (IAD) flight delay odds

81.1% of 1,886 official scheduled SEA-to-IAD flights arrived on time; 10.9% arrived at least 30 minutes late and 0.6% 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 SIGNALLower disruption
81.1%arrived on time
10.9%30+ min late
0.6%cancelled
1,886scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late5.6%all scheduled flights
120+ minutes late1.7%all scheduled flights
Diverted0.4%did not reach as scheduled
Average arrival-0.1 mincompleted flights

Which departure time was most reliable for SEA to IAD?

Among qualifying SEA-to-IAD departure window results, Early morning had the highest on-time rate: 88.7% of 467 flights. Night was lowest at 78.3% across 576 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning46788.7%5.6%0.6%
Late morning25979.2%12.7%0.4%
Afternoon58478.6%12.7%0.9%
Night57678.3%12.7%0.5%

Which weekday was most reliable for SEA to IAD?

Among qualifying SEA-to-IAD weekday results, Wednesday had the highest on-time rate: 86.4% of 258 flights. Sunday was lowest at 77.8% across 279 flights.

DayFlightsOn time30+ minCancelled
Monday27580.7%9.5%0.0%
Tuesday25883.3%8.1%0.0%
Wednesday25886.4%9.3%0.0%
Thursday27882.4%11.5%1.1%
Friday28178.6%11.7%1.1%
Saturday25778.6%12.5%0.4%
Sunday27977.8%13.6%1.8%

Which airline was most reliable for SEA to IAD?

Among qualifying SEA-to-IAD airline results, United Airlines had the highest on-time rate: 85.2% of 690 flights. Delta Air Lines was lowest at 75.9% across 361 flights.

AirlineFlightsOn time30+ minCancelled
Alaska Airlines83579.9%11.0%0.4%
United Airlines69085.2%8.4%0.7%
Delta Air Lines36175.9%15.5%1.1%

Which month was most reliable for SEA to IAD?

Among qualifying SEA-to-IAD month results, December 2025 had the highest on-time rate: 87.9% of 124 flights. July 2025 was lowest at 68.6% across 245 flights.

MonthFlightsOn time30+ minCancelled
July 202524568.6%20.8%0.4%
August 202522271.6%17.1%0.5%
September 202517987.2%5.0%0.0%
October 202515583.9%7.1%1.3%
November 202511984.0%11.8%0.0%
December 202512487.9%8.9%0.0%
January 202610280.4%12.7%2.9%
February 20269485.1%6.4%1.1%
March 202611782.9%10.3%0.9%
April 202612987.6%6.2%0.8%
May 202620285.1%6.4%0.0%
June 202619882.3%10.1%1.0%

What drove SEA to IAD delay minutes?

Airline was the largest recorded SEA-to-IAD delay category, accounting for 45.1% of 20,210 BTS-attributed delay minutes during July 2025–June 2026.

Airline45.1%
Late aircraft36.8%
National airspace14.7%
Weather3.2%
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.