SEA to DAL flight delays
Seattle, WA (SEA) Dallas, TX (DAL) · 1,670 miles
565 flights · July 2024 – July 2026 · US Bureau of Transportation Statistics
64.17%
Arrived on time
Within 15 minutes of schedule
0.35%
Cancelled
Share of scheduled flights
48 min
When late, late by
Average across delayed arrivals
19 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. Alaska Airlines arrived on time 33.5 points more often than Southwest Airlines over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The season swings this route hard. In April it ran 65.2 points more punctual than in June — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
The route has been getting worse. The later months run 31 points less punctual than the earlier ones. A drift of that size is rarely weather; it is more often an airline adding frequencies faster than the airports can absorb them.
This route does worse than its own airport. SEA as a whole runs 15.3 points more punctual than these flights, which points at something specific to the route — the time of day it is scheduled, or the aircraft that feed it — rather than the airport.
Which airline should you fly on this route?
Over July 2024 – July 2026, Alaska Airlines arrived on time most often on SEA to DAL. Southwest Airlines was late most often. Flights ran closest to schedule in October and worst in June.
Every airline on SEA to DAL
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 284 | 80.85% | 0.7% | 42 min | C |
| Southwest Airlines | 281 | 47.31% | 0% | 50 min | F |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
DAL to SEA Dallas back to Seattle 70% on time DOther routes from Seattle
Common questions
Are flights from Seattle to Dallas usually delayed?
64.17% of flights on the SEA to DAL route arrived within 15 minutes of schedule, so roughly 4 in every ten arrived late. That is worse than the average route in this record.
Which airline is most on time from Seattle to Dallas?
Alaska Airlines, at 80.85% on time across 284 flights. The least punctual on the route was Southwest Airlines at 47.31%.
How often are SEA to DAL flights cancelled?
0.35% of scheduled flights did not operate — about 4 in every thousand. That is in the normal range.
What is the best month to fly Seattle to Dallas?
April, when 91.7% of flights arrived on time. The worst was June at 26.5%.
When SEA to DAL flights are late, how late are they?
About 48 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on SEA to DAL during July 2024 – July 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →