67% of SEA → BOS flights arrived on time in June-August 2026 (893 flights). The most reliable was AS 1505, on time 97% of the time on this route. Evening flights did best (71%), morning flights worst (66%). Seattle (SEA): no delay reported. Boston Logan (BOS): no delay reported.
Best time of day to fly SEA → BOS
| Morning (before noon) | |
| Afternoon (noon-5 PM) | |
| Evening (after 5 PM) |
Flights SEA → BOS, most reliable first
| Flight | Departs | On time on this route | Cancelled |
|---|---|---|---|
| AS 1505 Alaska Airlines | 6:03 AM | 0% | |
| DL 459 Delta | 7:29 AM | 3.3% | |
| DL 473 Delta | 11:15 PM | 2.2% | |
| AS 536 Alaska Airlines | 11:18 PM | 0% | |
| AS 460 Alaska Airlines | 3:36 PM | 0% | |
| AS 306 Alaska Airlines | 8:23 AM | 0% | |
| AS 219 Alaska Airlines | 10:13 AM | 2.2% | |
| DL 474 Delta | 4:00 PM | 3.8% | |
| DL 438 Delta | 11:15 AM | 0% | |
| B6 198 JetBlue | 11:44 PM | 4.9% | |
| B6 398 JetBlue | 11:45 AM | 2.2% |
SEA conditions · BOS conditions · BOS → SEA · Cancellations
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From BTS on-time data, June-August 2026; flights with 20+ trips on this route. On-time rates cover each flight number's whole day, which can include other legs. Departure times are local.