Route on-time record
ONT to IAH: most on-time flights and the best time to fly
Ontario (Ontario International Airport) to Houston (George Bush Intercontinental Airport). 516 nonstop flights in Jun 2025 to May 2026, 85% arrived within 15 minutes and 0.6% were cancelled. The most reliable flight number was United 1936 at 6:00 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
ONT → IAH
Ontario to Houston: 516 nonstop flights a year
On time (12 months)
85%
Cancelled
0.6%
avg delay 16 min
Best time to leave
Before 9 AM
89% on time vs 71% 6 to 9 PM
Most reliable airline
United
88% 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 1936
6:00 AM → 11:11 AM3h 11m nonstop
Local times, typical schedule. Last flown 2026-05-31.
90%
chance on time
- On time (history)
- 91%
- Cancelled
- 0.3%
- Avg arrival delay
- 10 min
- Arrived on time 91% of the time (303 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 89% on time; 6 to 9 PM: 71%).
Strong track record · 303 flights
Find United 1936 fares Opens this date on Aviasales#2 · Frontier 3132
8:26 AM → 1:46 PM3h 20m nonstop
Local times, typical schedule. Last flown 2026-05-30.
75%
chance on time
- On time (history)
- 76%
- Cancelled
- 0.8%
- Avg arrival delay
- 28 min
- Arrived on time 76% of the time (127 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 89% on time; 6 to 9 PM: 71%).
- Lands inside IAH's trouble window: 60% of its 92 ground stops and delay programs started between noon and 6 PM.
- 53% of its delay minutes came from the plane arriving late from an earlier flight.
Moderate track record · 127 flights
Find Frontier 3132 fares Opens this date on Aviasales#3 · Frontier 2412
8:06 PM → 1:25 AM3h 19m nonstop
Local times, typical schedule. Last flown 2026-05-31.
72%
chance on time
- On time (history)
- 70%
- Cancelled
- 0.0%
- Avg arrival delay
- 24 min
- Arrived on time 70% of the time (23 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (6 to 9 PM: 71% on time; Before 9 AM: 89%).
- 84% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (23 flights), so its score leans on the airline's record at this hour.
Limited track record · 23 flights
Find Frontier 2412 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines88%
365 flights · 89% on time as flown · 0.6% cancel
- Frontier Airlines77%
151 flights · 75% on time as flown · 0.6% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM89%
377 flights · avg delay 12 min
- Noon to 3 PM76%
83 flights · avg delay 32 min
- 6 to 9 PM71%
31 flights · avg delay 19 min
Best day: Tuesday (92%). Worst: Monday (74%).
Smarter routing
Nearby airports that run more on time
SNA → IAH 88% chance on time
John Wayne Orange County International Airport to George Bush Intercontinental Airport · 1,094 flights a year · 30 mi from your airports · yours: 84%
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 aircraft43%
- Airline (crew, maintenance, boarding)35%
- Air traffic control and airport volume22%
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
ONT to IAH questions
- What time of day is best to fly ONT to IAH?
- Before 9 AM: 89% of flights arrived on time, against 71% 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 ONT to IAH?
- United, with a season-adjusted 88% chance of operating and arriving on time over 365 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 ONT to IAH?
- July (69% on time); the best was February (92%), 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 ONT
- IAH to ONT (return)
- ONT to PHX 83%
- ONT to DEN 79%
- ONT to SEA 86%
- ONT to LAS 78%
- ONT to DFW 78%
- ONT to SMF 86%
- ONT to OAK 87%
- ONT to SJC 86%
- ONT to SFO 69%
- ONT to SLC 91%
- ONT to ATL 90%
- ONT to PDX 88%
Live status: FAA delays and ground stops