Seattle to Boise

What the Data Says About SEA to BOI

The Seattle to Boise corridor (SEA → BOI) covers roughly 399 miles and is served by 8 carriers, based on Bureau of Transportation Statistics reporting. Across 25,171 flights in the dataset, this route posts a 86% on-time rate with an average delay of 58.6 minutes when flights run late. Over the most recent 24 months of BTS data, 7,670 flights were recorded on this pairing — 17 cancelled (0.2%) and 2 diverted (0.0%). Those baseline metrics tell you what to expect before you book.

Having 8 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 25,171 total flights analyzed, the 86% on-time figure is statistically meaningful rather than a small-sample fluke. The 58.6-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, Oct 2025 posted the best performance on this corridor at 92% on-time, while Feb 2025 came in at 70% on-time — a 22-point gap between best and worst recent month. For travelers evaluating the SEA to BOI route, the combination of a 86% on-time rate, 58.6-minute average delay, 0.2% recent cancellation rate, and 8 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.