Route on-time record

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

Seattle (Seattle–Tacoma International Airport) to Houston (George Bush Intercontinental Airport). 2,106 nonstop flights in Jun 2025 to May 2026, 78% arrived within 15 minutes and 0.9% were cancelled. The most reliable flight number was United 2135 at 6:30 AM.

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

SEA → IAH

Seattle to Houston: 2,106 nonstop flights a year

On time (12 months)

78%

Cancelled

0.9%

avg delay 13 min

Best time to leave

Before 9 AM

89% on time vs 66% 9 AM to noon

Most reliable airline

United

83% chance on time

Check SEA to IAH fares

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 2135
6:30 AM → 12:51 PM4h 21m nonstop
Local times, typical schedule. Last flown 2026-05-31.
90%
chance on time
On time (history)
91%
Cancelled
0.9%
Avg arrival delay
7 min
- Arrived on time 91% of the time (327 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 89% on time; 9 AM to noon: 66%).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Lands inside IAH's trouble window: 60% of its 92 ground stops and delay programs started between noon and 6 PM.
Strong track record · 327 flights
Find United 2135 fares Opens this date on Aviasales
#2 · United 2293
12:04 PM → 6:44 PM4h 40m nonstop
Local times, typical schedule. Last flown 2026-05-31.
85%
chance on time
On time (history)
100%
Cancelled
0.0%
Avg arrival delay
4 min
- Arrived on time 100% of the time (11 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 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 2293 fares Opens this date on Aviasales
#3 · United 1647
1:57 PM → 8:27 PM4h 30m nonstop
Local times, typical schedule. Last flown 2026-05-20. Same departure also flew as United 2860; its record covers all of them.
85%
chance on time
On time (history)
89%
Cancelled
0.0%
Avg arrival delay
9 min
- Arrived on time 89% of the time (53 flights, Jun 2025 to May 2026).
- Never cancelled in 53 scheduled flights.
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Short track record (53 flights), so its score leans on the airline's record at this hour.
Limited track record · 53 flights
Find United 1647 fares Opens this date on Aviasales
#4 · United 2693
11:35 PM → 5:56 AM4h 21m nonstop
Local times, typical schedule. Last flown 2026-04-29.
82%
chance on time
On time (history)
88%
Cancelled
0.0%
Avg arrival delay
6 min
- Arrived on time 88% of the time (32 flights, Jun 2025 to May 2026).
- Never cancelled in 32 scheduled flights.
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Short track record (32 flights), so its score leans on the airline's record at this hour.
Limited track record · 32 flights
Find United 2693 fares Opens this date on Aviasales
#5 · United 2748
5:00 AM → 11:21 AM4h 21m nonstop
Local times, typical schedule. Last flown 2026-05-30.
81%
chance on time
On time (history)
75%
Cancelled
0.0%
Avg arrival delay
9 min
- Arrived on time 75% of the time (8 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 89% on time; 9 AM to noon: 66%).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find United 2748 fares Opens this date on Aviasales
#6 · United 2379
11:59 PM → 6:20 AM4h 21m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 1303; its record covers all of them.
81%
chance on time
On time (history)
81%
Cancelled
1.5%
Avg arrival delay
14 min
- Arrived on time 81% of the time (260 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
Strong track record · 260 flights
Find United 2379 fares Opens this date on Aviasales
#7 · United 2340
2:15 PM → 8:40 PM4h 25m nonstop
Local times, typical schedule. Last flown 2026-03-28.
79%
chance on time
On time (history)
79%
Cancelled
0.0%
Avg arrival delay
12 min
- Arrived on time 79% of the time (80 flights, Jun 2025 to May 2026).
- Never cancelled in 80 scheduled flights.
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- 56% of its delay minutes came from the plane arriving late from an earlier flight.
Moderate track record · 80 flights
Find United 2340 fares Opens this date on Aviasales
#8 · Alaska 465
11:59 PM → 6:23 AM4h 24m nonstop
Local times, typical schedule. Last flown 2026-05-31.
76%
chance on time
On time (history)
100%
Cancelled
0.0%
Avg arrival delay
3 min
- Arrived on time 100% of the time (14 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Short track record (14 flights), so its score leans on the airline's record at this hour.
Limited track record · 14 flights
Find Alaska 465 fares Opens this date on Aviasales
#9 · United 1660
5:00 PM → 11:26 PM4h 26m nonstop
Local times, typical schedule. Last flown 2026-05-31.
76%
chance on time
On time (history)
50%
Cancelled
0.0%
Avg arrival delay
69 min
- Arrived on time 50% of the time (8 flights, Jun 2025 to May 2026).
- Departs inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.
- 91% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find United 1660 fares Opens this date on Aviasales
#10 · Alaska 398
11:01 PM → 5:21 AM4h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31.
76%
chance on time
On time (history)
78%
Cancelled
0.6%
Avg arrival delay
11 min
- Arrived on time 78% of the time (346 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
Strong track record · 346 flights
Find Alaska 398 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

United Airlines83%
1,251 flights · 83% on time as flown · 0.9% cancel
Alaska Airlines71%
855 flights · 71% on time as flown · 0.8% cancel

On time by departure time

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

Before 9 AM89%
447 flights · avg delay 10 min
9 AM to noon66%
466 flights · avg delay 17 min
Noon to 3 PM80%
263 flights · avg delay 13 min
3 to 6 PM79%
421 flights · avg delay 12 min
After 9 PM77%
508 flights · avg delay 13 min

Best day: Wednesday (82%). 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

Airline (crew, maintenance, boarding)38%
Late-arriving aircraft32%
Air traffic control and airport volume29%

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

SEA to IAH questions

What time of day is best to fly SEA to IAH?: Before 9 AM: 89% of flights arrived on time, against 66% for departures 9 AM to noon. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
Which airline is most on time from SEA to IAH?: United, with a season-adjusted 83% chance of operating and arriving on time over 1,251 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 SEA to IAH?: June (66% on time); the best was February (90%), 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 SEA

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