Best Time to Fly IAD to SEA
Washington to Seattle — month-by-month delay data from the Bureau of Transportation Statistics.
Best month
January
1% on time
Worst month
January
1% on time
IAD → SEA on-time performance by month
24
25
26
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
Better
Monthly breakdown
| Month | On-time | Cancel rate | Flights |
|---|---|---|---|
| January | 1% | 0.1% | 443 |
| February | 1% | 0% | 409 |
| March | 1% | 0% | 505 |
| April | 1% | 0% | 579 |
| May | 1% | 0% | 815 |
| June | 1% | 0% | 942 |
| July | 1% | 0% | 992 |
| August | 1% | 0% | 765 |
| September | 1% | 0% | 651 |
| October | 1% | 0% | 569 |
| November | 1% | 0% | 445 |
| December | 1% | 0% | 388 |
Frequently asked
What is the best month to fly from IAD to SEA?
January has the highest on-time rate at 1% for flights from Washington to Seattle.
What is the worst month to fly IAD to SEA?
January has the lowest on-time rate at 1%, often due to winter weather.
How often are IAD to SEA flights delayed?
On average, 1% of flights from IAD to SEA arrive on time. That means about 99% experience some form of delay.
Source: Bureau of Transportation Statistics.