Carrier route record
UABWI→IAH
United Airlines · Baltimore to Houston
- Flights
- 816
- Period
- July 2025 to June 2026
- Share of route
- 62%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on BWI to IAH lands a B, 6 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 816 flights, with a median arrival 12 minutes early.
Set against the rest of the country, United's BWI to IAH record is 6 points better than the US average of 77.6%. That gap is worth roughly 56 fewer late arrivals for every thousand flights.
Key figures
On time
83.2%
Arrivals under 15 minutes late, of 804 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.81%
Whole route
79.8%
Every carrier on BWI to IAH, 1,311 flights
These figures cover 816 flights between July 2025 and June 2026. The median arrival is 12 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.
Carrier by carrier
United against every carrier on BWI to IAH
United flew 816 of the 1,311 flights on BWI to IAH, most of the route. Its 83.2% on time is 3 points better than the route as a whole, which runs 79.8%. 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 66.4%. Two 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) | 816 | 83.2% | 80 min | 1.10% | B |
| Spirit Airlines | 376 | 76.5% | 108 min | 2.66% | B |
| Frontier Airlinesthin sample | 118 | 66.4% | 77 min | 4.24% | C− |
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 24 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am269 flights93.2%
- 8am–11am84 flights92.7%
- 11am–2pm132 flights86.9%
- 2pm–5pm210 flights72.5%
- 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 93.2% of the time, against 68.9% for the evening window. That is 24 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 269 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, Tuesday is the strongest day at 85.6% on time and Friday the weakest at 79.4%. 6 points is a smaller lever than departure hour, but it is free.
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 11,000 reported delay minutes.
- 34%National Airspace System
- 33%Carrier
- 22%Late-arriving aircraft
- 12%Extreme weather
Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.9 times the usual weather exposure. The split is drawn from 10,780 reported delay minutes.
34% 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 3,667 minutes out of 11,000, against a national NAS share of 21%.
Cancellations sit at 1.10% against a national 1.81%, which is ordinary. Diversions add another 0.37%.
Connections and stage length
What a delay here costs
5.7% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 77.9% on time across 814 flights, 5 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 5 points of difference.
One caution: this is a thin sample. 816 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. 816 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 83.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 804 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 IAH76.5%
- Frontier Airlines on BWI to IAH66.4%
- 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 7.04 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.