Itineraries flown on 20+ days in the Jun 6 – Jul 31, 2026 schedule · each leg’s record Aug 2025 – Jul 2026

No clear winner: airlines and hours on this route all land within a few points of 84% on time.

Nonstops


United	SEA	IAD	5h 07m	90%	0.8%	657	Flying now
Alaska	SEA	IAD	4h 58m	83%	0.4%	835	Flying now
Delta	SEA	IAD	5h 05m	77%	1.1%	361	Flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Dulles on time. Total trip = scheduled departure to arrival, layover included (Dulles is 3 h ahead of Seattle). Layovers up to 4 hours. Pick a connection for the details.


United Details →	SEA 06:00 → LAX 08:44UA 1692	1h 55m Los Angeles	LAX 10:39 → IAD 18:48UA 2667	9h 48m	100%	90%
United Details →	SEA 23:11 → ORD 05:18UA 747	3h 22m Chicago	ORD 08:40 → IAD 11:52 +1UA 2277	9h 41m	98%	90%
United Details →	SEA 17:04 → LAX 19:53UA 1730	1h 37m Los Angeles	LAX 21:30 → IAD 05:36 +1UA 2632	9h 32m	94%	88%
Delta Details →	SEA 23:10 → DTW 06:27DL 810	2h 23m Detroit	DTW 08:50 → IAD 10:23 +1DL 2884	8h 15m	99%	88%
Delta Details →	SEA 23:59 → MSP 05:17DL 953	2h 00m Minneapolis	MSP 07:17 → IAD 10:52 +1DL 3699 · flown by SkyWest	7h 53m	99%	87%
Delta Details →	SEA 22:58 → ATL 06:45DL 409	3h 05m Atlanta	ATL 09:50 → IAD 11:39 +1DL 1444	9h 40m	100%	85%
United Details →	SEA 10:29 → SFO 12:47UA 1482	3h 47m San Francisco	SFO 16:34 → IAD 00:55 +1UA 1453	11h 26m	98%	85%
Delta Details →	SEA 21:45 → ATL 05:36DL 567	2h 07m Atlanta	ATL 07:43 → IAD 09:26 +1DL 1324	8h 43m	98%	84%
Tight connection: often missed
Delta Details →	SEA 13:30 → SLC 16:40DL 1120	50m Salt Lake City	SLC 17:30 → IAD 23:30DL 847	7h 00m	74%	61%
United Details →	SEA 13:30 → SFO 15:48UA 737	46m San Francisco	SFO 16:34 → IAD 00:55 +1UA 1453	8h 25m	44%	38%
American Details →	SEA 11:40 → DFW 17:50AA 767	54m Dallas-Fort Worth	DFW 18:44 → IAD 22:46AA 1132	8h 12m	61%	27%

Same layover, different day-part

How often the first flight arrives too late to connect (45 min minimum), for one-ticket layovers of 45–80 minutes.

Morning

ORD · 1h 12m · leaves 23:11 12%

IAH · 52m · leaves 05:00 12%

Afternoon and evening

SLC · 50m · leaves 13:30 26%

DFW · 54m · leaves 11:40 39%

SFO · 46m · leaves 13:30 56%

Delays build through the day, so an afternoon first leg eats the layover. A short connection is fine early in the morning and a gamble later on.

Mixing airlines

One ticketMiss it and the airline rebooks you; bags go through. 45 min is enough.

Separate ticketsMiss it and you buy a new ticket. Re-check bags, clear security again: we require 90 min.


Alaska AS 394 SEA 21:33 → MCO United UA 276 MCO 08:55 → IAD Connection details →	2h 39m	10h 41m	99%	94%
Alaska AS 602 SEA 16:26 → DEN United UA 1924 DEN 23:59 → IAD Connection details →	3h 49m	10h 01m	99%	92%
Alaska AS 639 SEA 21:18 → TPA United UA 2331 TPA 09:00 → IAD Connection details →	3h 12m	11h 04m	99%	92%

Rank all connections, any airlines →

Regional partners count as the airline that sells them: SkyWest flying Delta Connection is one Delta ticket.

How these are worked out. Makes the connection: share of the last year’s flights where the first flight arrived with at least 45 minutes to spare (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled and arriving within 15 minutes. Not yet counted: the second flight also leaving late (which helps), gate-to-gate distance at the hub, and rebooking after a missed connection.

About this data: US DOT on-time records, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. Schedules (which flights and connections exist, and their times) are as of Jun 6 – Jul 31, 2026; seasonal flights outside that window aren’t ranked. Rebuilt monthly. JSON