Carrier route record
UABWI→IAH
United Airlines · Baltimore to Houston
- Flights
- 833
- Period
- September 2025 to August 2026
- Share of route
- 64%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on BWI to IAH earns a B. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 833 flights, with a median arrival 13 minutes early.
Set against the rest of the country, United's BWI to IAH record is 7 points better than the US average of 77.3%. That gap is worth roughly 67 fewer late arrivals for every thousand flights.
Key figures
On time
84.0%
Arrivals under 15 minutes late, of 821 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
1.20%
National rate is 1.89%
Whole route
78.3%
Every carrier on BWI to IAH, 1,307 flights
These figures cover 833 flights between September 2025 and August 2026. The median arrival is 13 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
United against every carrier on BWI to IAH
United flew 833 of the 1,307 flights on BWI to IAH, most of the route. Its 84.0% on time is 6 points better than the route as a whole, which runs 78.3%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from SkyWest at 100.0% to Frontier at 59.1%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| United Airlines (this page) | 833 | 84.0% | 68 min | 1.20% | B |
| Spirit Airlinesthin sample | 293 | 73.3% | 103 min | 2.73% | C |
| Frontier Airlinesthin sample | 180 | 59.1% | 90 min | 5.00% | D− |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against half a point between the best and worst carrier.
- 5am–8am236 flights94.0%
- 8am–11am84 flights92.7%
- 11am–2pm182 flights87.7%
- 2pm–5pm210 flights75.0%
- 5pm–8pm121 flights68.9%
- 8pm–5am—
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.0% of the time, against 68.9% for the evening window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 236 flights scheduled in it.
Across the year
United on BWI to IAH through the year
Delays peak in May, when the on-time rate falls to 72.0%. January is the strongest month at 92.0%. Moving a flexible trip across that boundary buys 20 points. April was the busiest month here, with 82 flights.
Across the week, Thursday is the strongest day at 88.0% on time and Friday the weakest at 80.5%, a spread of 8 points.
Arrival by arrival
How late United on BWI to IAH runs when it is late
United on BWI to IAH often beats the schedule: 385 of 821 completed flights, 47%, arrived 15 minutes or more early. The 131 late arrivals split 46 under half an hour, 44 between 30 and 60 minutes, and 41 an hour or more.
- 15+ min early385 flights46.9%
- Within 15 min305 flights37.1%
- 15–29 min late46 flights5.6%
- 30–59 min late44 flights5.4%
- 1–2 hours late23 flights2.8%
- 2+ hours late18 flights2.2%
Scale runs 0% to 100%.
Share of 821 completed flights by arrival against schedule.
27 of 110 late departures made up the time and arrived on time, 25% of them. In the other direction, 48 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at IAH.
The worst days
Worst days for United on BWI to IAH
The latest arrival of the period was on 30 November 2025, 13 hours 11 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 30 November 2025 | 13 hours 11 minutes | Carrier |
| 15 December 2025 | 6 hours 45 minutes | Late-arriving aircraft |
| 16 March 2026 | 5 hours 41 minutes | Carrier |
| 31 December 2025 | 4 hours 42 minutes | Carrier |
| 18 July 2026 | 4 hours 15 minutes | Extreme weather |
Delay causes
Why United runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 8,846 reported delay minutes.
- 37%National Airspace System
- 28%Carrier
- 27%Late-arriving aircraft
- 8%Extreme weather
37% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,247 minutes out of 8,846, against a national NAS share of 21%. The split is drawn from 8,846 reported delay minutes.
Cancellations sit at 1.20% against a national 1.89%, which is ordinary. Diversions add another 0.24%.
Connections and stage length
What a delay here costs
5.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 1,235 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg runs 81.3% on time across 831 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 833 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking United on BWI to IAH
Put together: treat all of this as provisional. 833 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 84.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 821 completed flights over 12 months sit behind that.
Related
Where to go next
- BWI to IAH, every carrier
- United on IAH to BWI, the return leg
- Spirit Airlines on BWI to IAH73.3%
- Frontier Airlines on BWI to IAH59.1%
- United Airlines network-wide record
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.