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 83% on time.

Nonstops


Delta	SMF	SEA	2h 14m	89%	0.2%	1,634	Flying now
Alaska	SMF	SEA	2h 05m	81%	0.7%	1,786	Flying now
Southwest	SMF	SEA	2h 00m	79%	0.2%	1,139	Flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Seattle on time. Total trip = scheduled departure to arrival, layover included. Layovers up to 4 hours. Pick a connection for the details.


Delta Details →	SMF 06:00 → LAX 07:40DL 3969 · flown by SkyWest	2h 00m Los Angeles	LAX 09:40 → SEA 12:30DL 1714	6h 34m	96%	89%
Delta Details →	SMF 17:00 → SLC 19:43DL 1342	3h 02m Salt Lake City	SLC 22:45 → SEA 23:59DL 2998	6h 59m	98%	88%
Delta Details →	SMF 05:30 → SLC 08:11DL 1526	3h 24m Salt Lake City	SLC 11:35 → SEA 12:52DL 2995	7h 22m	99%	87%
United Details →	SMF 08:50 → DEN 12:16UA 2285	1h 44m Denver	DEN 14:00 → SEA 16:00UA 2164	7h 10m	99%	82%
Delta Details →	SMF 09:21 → LAX 10:58DL 3700 · flown by SkyWest	3h 02m Los Angeles	LAX 14:00 → SEA 16:47DL 2606	7h 26m	98%	81%
Alaska Details →	SMF 08:13 → PDX 09:47AS 2095 · flown by Horizon	2h 16m Portland	PDX 12:03 → SEA 13:03AS 3078 · flown by SkyWest	4h 50m	97%	81%
Delta Details →	SMF 14:15 → LAX 15:52DL 3812 · flown by SkyWest	1h 53m Los Angeles	LAX 17:45 → SEA 20:34DL 2640	6h 19m	97%	80%
Alaska Details →	SMF 11:46 → PDX 13:18AS 621	2h 12m Portland	PDX 15:30 → SEA 16:30AS 3408 · flown by SkyWest	4h 44m	100%	78%
Tight connection: often missed
Alaska Details →	SMF 17:37 → SAN 19:21AS 3036 · flown by SkyWest	1h 14m San Diego	SAN 20:35 → SEA 23:41AS 1362	6h 04m	70%	48%
Alaska Details →	SMF 08:36 → SAN 10:20AS 3015 · flown by SkyWest	1h 01m San Diego	SAN 11:21 → SEA 14:25AS 475	5h 49m	71%	41%
United Details →	SMF 11:46 → SFO 12:53UA 5248 · flown by SkyWest	1h 07m San Francisco	SFO 14:00 → SEA 16:20UA 1265	4h 34m	64%	36%

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

LAS · 50m · leaves 05:25 10%

LAX · 1h 01m · leaves 09:21 16%

DEN · 50m · leaves 05:55 18%

Afternoon and evening

PDX · 1h 03m · leaves 14:55 23%

SAN · 1h 14m · leaves 17:37 30%

PHX · 1h 00m · leaves 19:50 43%

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.


Southwest WN 3829 SMF 06:10 → SNA Alaska AS 471 SNA 10:28 → SEA Connection details →	2h 53m	7h 07m	100%	92%
Southwest WN 3760 SMF 05:40 → BOI Delta DL 3678 BOI 11:55 → SEA Connection details →	3h 50m	7h 02m	100%	92%
Southwest WN 949 SMF 10:12 → PDX Delta DL 4062 PDX 15:26 → SEA Connection details →	3h 44m	6h 29m	100%	89%

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