Flight Reliability
AS 128 · Alaska Airlines
Portland → San Francisco (PDX–SFO)100% of its flights flew this route. The rest (ATL–SEA) are included in these numbers.
86
Pretty Reliable
WanderNerd Reliability Score
- 82%
- Arrive within 15 minutes
- 5 min
- Average arrival delay
- 1.0%
- Cancelled
- 2 min early
- Median arrival delay
Based on 292 historical flights. Data through May 2026.
What the data says
Friday is doing you no favors.
AS 128 arrived on time 93% of the time on Sundays and just 72% on Fridays. That gap is worth planning around.
A bit ahead of the PDX–SFO route.
AS 128 arrived on time 82% of the time, versus 76% across the PDX–SFO route.
Recent months have been rougher.
AS 128 arrived on time 78% of the time over the last three months in the data, compared with 87% in the three months before that.
The breakdown
- Mon81%(42 flights)
- Tue88%(42 flights)
- Wed79%(42 flights)
- Thu75%(40 flights)
- Fri72%(39 flights)
- Sat88%(41 flights)
- Sun93%(43 flights)
- 9 AM–12 PM82%(288 flights)
- 6–9 PM—(1 flights)
71%
Apr
Jun 97% → Apr 71% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 97% | 30 |
| July 2025 | 65% | 31 |
| August 2025 | 90% | 31 |
| September 2025 | 90% | 30 |
| October 2025 | 65% | 31 |
| November 2025 | 93% | 28 |
| December 2025 | 80% | 30 |
| January 2026 | 87% | 31 |
| February 2026 | 64% | 11 |
| March 2026 | 100% | 15 |
| April 2026 | 71% | 21 |
- Departures on time
- 80%
- Diverted
- 0%
- Flights flown
- 289
- Months covered
- 11
Same route, other flights
Keep nerding
Based on 292 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.