Route on-time record
DEN to SEA: most on-time flights and the best time to fly
Denver (Denver International Airport) to Seattle (Seattle–Tacoma International Airport). 6,318 nonstop flights in Jun 2025 to May 2026, 73% arrived within 15 minutes and 0.7% were cancelled. The most reliable flight number was United 1482 at 6:00 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
DEN → SEA
Denver to Seattle: 6,318 nonstop flights a year
On time (12 months)
73%
Cancelled
0.7%
avg delay 17 min
Best time to leave
Before 9 AM
85% on time vs 58% after 9 PM
Most reliable airline
United
79% chance on time
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 · United 1482
6:00 AM → 8:00 AM3h 00m nonstop
Local times, typical schedule. Last flown 2026-05-31.
91%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 1 min
- Arrived on time 100% of the time (11 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; After 9 PM: 58%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
- Short track record (11 flights), so its score leans on the airline's record at this hour.
Limited track record · 11 flights
Find United 1482 fares Opens this date on Aviasales#2 · United 2271
7:45 AM → 9:46 AM3h 01m nonstop
Local times, typical schedule. Last flown 2026-05-31.
89%
chance on time
- On time (history)
- 91%
- Cancelled
- 1.1%
- Avg arrival delay
- 4 min
- Arrived on time 91% of the time (281 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; After 9 PM: 58%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Strong track record · 281 flights
Find United 2271 fares Opens this date on Aviasales#3 · Alaska 647
6:00 AM → 8:03 AM3h 03m nonstop
Local times, typical schedule. Last flown 2026-05-12.
87%
chance on time
- On time (history)
- 95%
- Cancelled
- 0.0%
- Avg arrival delay
- 2 min
- Arrived on time 95% of the time (21 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; After 9 PM: 58%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
- Short track record (21 flights), so its score leans on the airline's record at this hour.
Limited track record · 21 flights
Find Alaska 647 fares Opens this date on Aviasales#4 · Delta 1731
6:30 AM → 8:38 AM3h 06m nonstop
Local times, typical schedule. Last flown 2026-05-31.
87%
chance on time
- On time (history)
- 88%
- Cancelled
- 0.8%
- Avg arrival delay
- 13 min
- Arrived on time 88% of the time (361 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; After 9 PM: 58%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Strong track record · 361 flights
Find Delta 1731 fares Opens this date on Aviasales#5 · Alaska 643
7:00 AM → 9:10 AM3h 10m nonstop
Local times, typical schedule. Last flown 2026-05-31.
87%
chance on time
- On time (history)
- 87%
- Cancelled
- 0.0%
- Avg arrival delay
- 11 min
- Arrived on time 87% of the time (295 flights, Jun 2025 to May 2026).
- Never cancelled in 295 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; After 9 PM: 58%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Strong track record · 295 flights
Find Alaska 643 fares Opens this date on Aviasales#6 · Delta 1358
1:08 PM → 3:10 PM3h 02m nonstop
Local times, typical schedule. Last flown 2026-05-31.
84%
chance on time
- On time (history)
- 88%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 88% of the time (25 flights, Jun 2025 to May 2026).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
- Short track record (25 flights), so its score leans on the airline's record at this hour.
Limited track record · 25 flights
Find Delta 1358 fares Opens this date on Aviasales#7 · United 1424
11:15 AM → 1:16 PM3h 01m nonstop
Local times, typical schedule. Last flown 2026-05-31.
84%
chance on time
- On time (history)
- 86%
- Cancelled
- 1.0%
- Avg arrival delay
- 12 min
- Arrived on time 86% of the time (195 flights, Jun 2025 to May 2026).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Moderate track record · 195 flights
Find United 1424 fares Opens this date on Aviasales#8 · Alaska 682
11:47 AM → 1:53 PM3h 03m nonstop
Local times, typical schedule. Last flown 2026-05-31.
80%
chance on time
- On time (history)
- 81%
- Cancelled
- 0.7%
- Avg arrival delay
- 11 min
- Arrived on time 81% of the time (271 flights, Jun 2025 to May 2026).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Strong track record · 271 flights
Find Alaska 682 fares Opens this date on Aviasales#9 · United 2013
3:59 PM → 6:00 PM3h 01m nonstop
Local times, typical schedule. Last flown 2026-05-31.
80%
chance on time
- On time (history)
- 84%
- Cancelled
- 0.5%
- Avg arrival delay
- 12 min
- Arrived on time 84% of the time (199 flights, Jun 2025 to May 2026).
- Departs inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- Lands inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.
Moderate track record · 199 flights
Find United 2013 fares Opens this date on Aviasales#10 · Frontier 4545
7:15 AM → 9:27 AM3h 09m nonstop
Local times, typical schedule. Last flown 2026-05-31.
80%
chance on time
- On time (history)
- 80%
- Cancelled
- 1.2%
- Avg arrival delay
- 13 min
- Arrived on time 80% of the time (162 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; After 9 PM: 58%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Moderate track record · 162 flights
Find Frontier 4545 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines79%
1,904 flights · 79% on time as flown · 0.6% cancel
- Delta Air Lines77%
868 flights · 77% on time as flown · 0.9% cancel
- Alaska Airlines72%
1,571 flights · 72% on time as flown · 0.9% cancel
- Frontier Airlines72%
412 flights · 72% on time as flown · 1.4% cancel
- SkyWest Airlines (sold as United Express, Delta Connection, American Eagle or Alaska)71%
220 flights · 76% on time as flown · 0.6% cancel
- Southwest Airlines62%
1,343 flights · 62% on time as flown · 0.3% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM85%
1,700 flights · avg delay 9 min
- 9 AM to noon78%
733 flights · avg delay 15 min
- Noon to 3 PM79%
907 flights · avg delay 14 min
- 3 to 6 PM65%
1,072 flights · avg delay 21 min
- 6 to 9 PM62%
1,408 flights · avg delay 25 min
- After 9 PM58%
498 flights · avg delay 25 min
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
- Late-arriving aircraft46%
- Airline (crew, maintenance, boarding)34%
- Air traffic control and airport volume17%
- 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
DEN to SEA questions
- What time of day is best to fly DEN to SEA?
- Before 9 AM: 85% of flights arrived on time, against 58% for departures after 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 DEN to SEA?
- United, with a season-adjusted 79% chance of operating and arriving on time over 1,904 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 DEN to SEA?
- June (65% on time); the best was November (83%), 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 DEN
- SEA to DEN (return)
- DEN to PHX 75%
- DEN to SLC 77%
- DEN to LAX 79%
- DEN to LAS 75%
- DEN to ORD 70%
- DEN to DFW 75%
- DEN to SAN 76%
- DEN to MSP 78%
- DEN to ATL 80%
- DEN to SFO 68%
- DEN to AUS 76%
- DEN to COS 75%
Live status: FAA delays and ground stops