Portland to Seattle

What the Data Says About PDX to SEA

The Portland to Seattle corridor (PDX → SEA) covers roughly 129 miles and is served by 19 carriers, based on Bureau of Transportation Statistics reporting. Across 36,148 flights in the dataset, this route posts a 87.7% on-time rate with an average delay of 65.3 minutes when flights run late. Over the most recent 24 months of BTS data, 10,310 flights were recorded on this pairing — 98 cancelled (1.0%) and 6 diverted (0.1%). Those baseline metrics tell you what to expect before you book.

Having 19 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 36,148 total flights analyzed, the 87.7% on-time figure is statistically meaningful rather than a small-sample fluke. The 65.3-minute average delay applies only to flights that actually ran late, so it is not the average wait across all departures — the majority of flights on this route depart on time under the BTS definition of a delay (15+ minutes past schedule).

Looking at recent months, Nov 2024 posted the best performance on this corridor at 93% on-time, while Jun 2025 came in at 75% on-time — a 18-point gap between best and worst recent month. For travelers evaluating the PDX to SEA route, the combination of a 87.7% on-time rate, 65.3-minute average delay, 1.0% recent cancellation rate, and 19 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.