79% of flights from Sun Valley to Seattle arrived on time over the past 12 months. That is about the typical U.S. route. 7% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SUN → SEA: when a flight was late, it was under 45 minutes late 70% of the time. About 1 in 22 flights landed an hour or more late, and 1 in 78 three hours or more; 1.9% were cancelled outright.
- On time or early79%
- 15–30 min late9.0%
- 30–60 min late5.3%
- 1–2 hours late2.4%
- 2–3 hours late0.9%
- 3+ hours late1.3%
- Diverted0.4%
- Cancelled1.9%
Share of all 468 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Alaska Airlines | 430 | 78% | 1.9% | −8 min | 4.4% | +53 min | Horizon Air |
| Delta Air Lines | 38 | — | — | — | — | — | SkyWest |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at SUN). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | Alaska Airlines |
|---|---|
| 10 a.m. | 77% |
Last flight of the day
On SUN → SEA, each airline's last flight of the day was cancelled 4.0% of the time, against 1.6% for its earlier flights (2.5× as often). It arrived 3+ hours late 0.8% of the time (earlier flights: 0.8%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Alaska Airlines | 10:21 a.m. | 4.0% | 0.8% | 1.6% | first flight 10:20 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in SEA tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: March (83%). Worst: August (58%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 67 | — | — |
| Tuesday | 56 | — | — |
| Wednesday | 48 | — | — |
| Thursday | 70 | — | — |
| Friday | 76 | — | — |
| Saturday | 67 | — | — |
| Sunday | 84 | — | — |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 8 · airline 1
Month by month
Not enough months with data to draw a trend.
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Dec 31, 2025 | 3 | 0% | 0 |
| Mar 13, 2026 | 3 | 0% | 2 |
| Dec 27, 2025 | 3 | 33% | 1 |
| Dec 21, 2025 | 3 | 33% | 1 |
| Dec 20, 2025 | 3 | 33% | 0 |
Questions
How often are flights from SUN to SEA on time?
79% of 468 scheduled flights from Sun Valley/Hailey/Ketchum, ID to Seattle, WA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.9% were cancelled.
What month has the most delays from SUN to SEA?
August (58% on time). The best month is March (83%), over 2023–2026.
Is the last flight of the day from SUN to SEA more likely to be cancelled?
Yes. Each airline's last SUN–SEA flight of the day was cancelled 4.0% of the time over the past year, against 1.6% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- SEA → SUN (return)
- Friedman Memorial (SUN) delays by hour
- Flights into Seattle-Tacoma (SEA)
- Alaska Airlines on-time record
- Delta Air Lines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.