ON TIMEBOARD

AS 311 on time

Alaska Airlines 311: Boston to Portland at 6:03 a.m. (past 12 months)

On time
87%
156 flights · likely 81–92%
Cancelled
0.0%
of scheduled flights
Typical arrival
−7 min
median vs schedule
When late
+34 min
average delay
Similar flights
90%
AS, same route & hour

About 1 in 8 AS 311 flights from Boston arrived 15+ minutes late, diverted or cancelled over the past year (13%); 0.0% were cancelled. The typical flight landed 7 minutes early.

AS 311: BOS → PDX

Scheduled to leave Boston at 6:03 a.m. local time. Over the past year it arrived on time 87% of the time (156 flights), in line with other AS flights on the route at that hour (90%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%May 2025: 94% on time (17 flights)94MayJun 2025: 100% on time (30 flights)100JunJul 2025: too few flights (3 flights)JulNov 2025: too few flights (9 flights)NovDec 2025: too few flights (8 flights)DecJan 2026: too few flights (4 flights)JanMar 2026: too few flights (10 flights)MarApr 2026: 100% on time (15 flights)100AprMay 2026: 94% on time (18 flights)94MayJun 2026: 100% on time (30 flights)100JunJul 2026: 94% on time (31 flights)94JulAug 2026: 87% on time (31 flights)87Aug

By day of week

DayFlightsOn time
Monday2677%
Tuesday2483%
Wednesday16—
Thursday2391%
Friday2677%
Saturday2391%
Sunday18—

Why it was late

Air traffic & airport (NAS) 72%Airline (crew, maintenance, ops) 25%Severe weather 3%

All flights BOS → PDX · Connecting off AS 311? Check the risk

Questions

How often is AS 311 from BOS to PDX late?

Alaska Airlines 311 from Boston, MA to Portland, OR arrived 15 or more minutes late, was diverted or was cancelled on 13% of 156 scheduled flights between September 2025 and August 2026. 0.0% 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.