Route on-time record

BOS to SEA: most on-time flights and the best time to fly

Boston (Boston Logan International Airport) to Seattle (Seattle–Tacoma International Airport). 2,438 nonstop flights in Jun 2025 to May 2026, 70% arrived within 15 minutes and 1.2% were cancelled. The most reliable flight number was JetBlue 397 at 7:00 AM.

Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.

BOS → SEA

Boston to Seattle: 2,438 nonstop flights a year

On time (12 months)

70%

Cancelled

1.2%

avg delay 17 min

Best time to leave

Before 9 AM

76% on time vs 58% 6 to 9 PM

Most reliable airline

JetBlue

73% chance on time

Check BOS to SEA fares

Lowest nonstop fare seen in the next two months: $404 (Alaska 288 on 2026-10-27). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

#1 · JetBlue 397
7:00 AM → 10:17 AM6h 17m nonstop
Local times, typical schedule. Last flown 2026-05-31.
85%
chance on time
On time (history)
90%
Cancelled
0.6%
Avg arrival delay
9 min
- Arrived on time 90% of the time (164 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 76% on time; 6 to 9 PM: 58%).
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
Moderate track record · 164 flights
Find JetBlue 397 fares Opens this date on Aviasales
#2 · Delta 332
11:15 AM → 2:35 PM6h 13m nonstop
Local times, typical schedule. Last flown 2026-05-31.
79%
chance on time
On time (history)
80%
Cancelled
0.0%
Avg arrival delay
12 min
- Arrived on time 80% of the time (229 flights, Jun 2025 to May 2026).
- Never cancelled in 230 scheduled flights.
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
Strong track record · 229 flights
Find Delta 332 fares Opens this date on Aviasales
#3 · Alaska 1437
4:33 PM → 7:55 PM6h 22m nonstop
Local times, typical schedule. Last flown 2026-05-12.
75%
chance on time
On time (history)
86%
Cancelled
0.0%
Avg arrival delay
4 min
- Arrived on time 86% of the time (14 flights, Jun 2025 to May 2026).
- Departs inside BOS's trouble window: 79% of its 196 ground stops and delay programs started between noon and 6 PM.
- Lands inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.
- Short track record (14 flights), so its score leans on the airline's record at this hour.
Limited track record · 14 flights
Find Alaska 1437 fares Opens this date on Aviasales
#4 · Delta 384
7:10 AM → 10:55 AM6h 18m nonstop
Local times, typical schedule. Last flown 2026-05-31.
74%
chance on time
On time (history)
75%
Cancelled
1.6%
Avg arrival delay
11 min
- Arrived on time 75% of the time (358 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 76% on time; 6 to 9 PM: 58%).
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
Strong track record · 358 flights
Find Delta 384 fares Opens this date on Aviasales
#5 · Alaska 537
9:01 AM → 12:18 PM6h 17m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Alaska 215; its record covers all of them.
73%
chance on time
On time (history)
73%
Cancelled
0.6%
Avg arrival delay
17 min
- Arrived on time 73% of the time (318 flights, Jun 2025 to May 2026).
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
Strong track record · 318 flights
Find Alaska 537 fares Opens this date on Aviasales
#6 · Alaska 260
4:48 PM → 8:10 PM6h 22m nonstop
Local times, typical schedule. Last flown 2026-05-31.
71%
chance on time
On time (history)
74%
Cancelled
0.0%
Avg arrival delay
18 min
- Arrived on time 74% of the time (19 flights, Jun 2025 to May 2026).
- Departs inside BOS's trouble window: 79% of its 196 ground stops and delay programs started between noon and 6 PM.
- Lands inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.
- Short track record (19 flights), so its score leans on the airline's record at this hour.
Limited track record · 19 flights
Find Alaska 260 fares Opens this date on Aviasales
#7 · Alaska 459
7:00 AM → 10:40 AM6h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31.
71%
chance on time
On time (history)
71%
Cancelled
0.8%
Avg arrival delay
14 min
- Arrived on time 71% of the time (358 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 76% on time; 6 to 9 PM: 58%).
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
Strong track record · 358 flights
Find Alaska 459 fares Opens this date on Aviasales
#8 · Alaska 299
6:24 PM → 10:00 PM6h 36m nonstop
Local times, typical schedule. Last flown 2026-03-17.
64%
chance on time
On time (history)
67%
Cancelled
2.9%
Avg arrival delay
13 min
- Arrived on time 67% of the time (33 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (6 to 9 PM: 58% on time; Before 9 AM: 76%).
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
- Short track record (33 flights), so its score leans on the airline's record at this hour.
Limited track record · 33 flights
Find Alaska 299 fares Opens this date on Aviasales
#9 · Delta 2889
3:55 PM → 7:05 PM6h 10m nonstop
Local times, typical schedule. Last flown 2026-05-31.
63%
chance on time
On time (history)
60%
Cancelled
0.0%
Avg arrival delay
19 min
- Arrived on time 60% of the time (20 flights, Jun 2025 to May 2026).
- Departs inside BOS's trouble window: 79% of its 196 ground stops and delay programs started between noon and 6 PM.
- Lands inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.
- Short track record (20 flights), so its score leans on the airline's record at this hour.
Limited track record · 20 flights
Find Delta 2889 fares Opens this date on Aviasales
#10 · Delta 324
6:45 PM → 10:10 PM6h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31.
62%
chance on time
On time (history)
63%
Cancelled
2.5%
Avg arrival delay
24 min
- Arrived on time 63% of the time (354 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (6 to 9 PM: 58% on time; Before 9 AM: 76%).
- Departs outside BOS's trouble window (noon to 6 PM, when 79% of its 196 ground stops and delay programs started).
Strong track record · 354 flights
Find Delta 324 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

JetBlue73%
248 flights · 76% on time as flown · 0.7% cancel
Delta Air Lines71%
979 flights · 72% on time as flown · 1.5% cancel
Alaska Airlines68%
1,211 flights · 68% on time as flown · 1.1% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

Before 9 AM76%
889 flights · avg delay 12 min
9 AM to noon76%
558 flights · avg delay 15 min
3 to 6 PM75%
234 flights · avg delay 14 min
6 to 9 PM58%
757 flights · avg delay 26 min

Best day: Monday (79%). Worst: Friday (73%).

On time by month

All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.

What delays this route

Air traffic control and airport volume36%
Late-arriving aircraft36%
Airline (crew, maintenance, boarding)24%
Severe weather2%

Share of delay minutes by the cause airlines report to the US DOT.

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure

BOS to SEA questions

What time of day is best to fly BOS to SEA?: Before 9 AM: 76% of flights arrived on time, against 58% for departures 6 to 9 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
Which airline is most on time from BOS to SEA?: JetBlue, with a season-adjusted 73% chance of operating and arriving on time over 248 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
What is the worst month for delays on BOS to SEA?: June (66% on time); the best was September (85%), averaged over Jun 2023 to May 2026.
Is this a prediction for my flight?: No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.

More routes from BOS

Live status: FAA delays and ground stops

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