About 1 in 4 AS 2109 flights from Seattle arrived 15+ minutes late, diverted or cancelled over the past year (22%); 0.6% were cancelled. The typical flight landed 2 minutes early.
AS 2109: SEA → BOI
Scheduled to leave Seattle at 5:40 p.m. local time, operated by Horizon Air as QX 2109. Over the past year it arrived on time 78% of the time (156 flights), in line with other AS flights on the route at that hour (80%). Last seen in the data Aug 18, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 23 | 78% |
| Tuesday | 21 | 76% |
| Wednesday | 21 | 71% |
| Thursday | 22 | 82% |
| Friday | 23 | 78% |
| Saturday | 23 | 70% |
| Sunday | 23 | 87% |
Why it was late
All flights SEA → BOI · Connecting off AS 2109? Check the risk
Questions
How often is AS 2109 from SEA to BOI late?
Alaska Airlines 2109 from Seattle, WA to Boise, ID arrived 15 or more minutes late, was diverted or was cancelled on 22% of 156 scheduled flights between September 2025 and August 2026. 0.6% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Alaska Airlines for today's flight. Method.