San Francisco to Seattle

What the Data Says About SFO to SEA

The San Francisco to Seattle corridor (SFO → SEA) covers roughly 679 miles and is served by 26 carriers, based on Bureau of Transportation Statistics reporting. Across 37,671 flights in the dataset, this route posts a 82.1% on-time rate with an average delay of 62.8 minutes when flights run late. Over the most recent 24 months of BTS data, 13,519 flights were recorded on this pairing — 177 cancelled (1.3%) and 9 diverted (0.1%). Those baseline metrics tell you what to expect before you book.

Having 26 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 37,671 total flights analyzed, the 82.1% on-time figure is statistically meaningful rather than a small-sample fluke. The 62.8-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, Jan 2025 posted the best performance on this corridor at 88% on-time, while Jun 2025 came in at 66% on-time — a 22-point gap between best and worst recent month. For travelers evaluating the SFO to SEA route, the combination of a 82.1% on-time rate, 62.8-minute average delay, 1.3% recent cancellation rate, and 26 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.