Route reliability record
IAH→PDX
Houston to Portland
- Flights
- 1,209
- Period
- September 2025 to August 2026
- Distance
- 1,825 mi
- Carriers
- 2
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 1,209 IAH to PDX flights, with a median arrival 7 minutes early.
Best time to fly IAH to PDX: a 8am–11am departure, ideally on a Sunday. Flights in that window arrived on time 86.8% of the time and Sunday flights 81.7%, against 80.9% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.9%
Arrivals under 15 minutes late, of 1,199 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.50%
National rate is 1.89%
Best carrier
United
82.3% on time across 856 flights
These figures cover 1,209 flights between September 2025 and August 2026. The median arrival is 7 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
Which airline is most reliable on IAH to PDX
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 |
|---|---|---|---|---|---|
| United Airlines | 856 | 82.3% | 62 min | 0.23% | B+ |
| Alaska Airlinesthin sample | 353 | 77.6% | 61 min | 1.13% | B |
Flight by flight
Flights on IAH to PDX
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 11 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am365 flights86.8%
- 11am–2pm—
- 2pm–5pm166 flights85.4%
- 5pm–8pm338 flights76.0%
- 8pm–5am340 flights77.2%
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 86.8% of the time, against 76.0% for the evening window. That is 11 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 365 flights scheduled in it.
Explore
Filter IAH to PDX by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On IAH to PDX, the best departure window is 8am–11am at 86.8% on time and the worst is 5pm–8pm at 76.0%, a wide gap of 10.8 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am86.8%
- 11am–2pm—
- 2–5pm85.4%
- 5–8pm76.0%
- 8pm–5am77.2%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 16 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 73.7% on time, 16 points below April, the best at 89.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. May was the busiest month here, with 119 flights.
The day of the week is close to irrelevant here: about a point separates the best day from the worst. Weekly demand peaks are not what drives the delays on this operation.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 50% of the 14,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Late-arriving aircraft
- 25%Carrier
- 14%National Airspace System
- 10%Extreme weather
- 1%Security
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 14,000 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 14,146 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.8% on time here.
Cancellations are rare at 0.50%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
6.1% 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.
At 1,825 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 86.6% on time across 1,208 flights, 6 points above 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 6 points of difference.
The sample behind these figures is 1,209 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in PDX after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 89.9% on time and June 73.7%, a swing of 16 points. If the dates move at all, move them out of June before you think about anything else. 1,199 completed flights over 12 months sit behind that.
Common questions
IAH to PDX questions
How often is IAH to PDX delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.1% of the 1,209 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is IAH to PDX compared with the rest of the country?
80.9% of flights arrive on time here against a national 77.3%, a difference of 4 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on IAH to PDX?
The 8am–11am departure window is the strongest at 86.8% on time. The 5pm–8pm window is the weakest at 76.0%, 11 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on IAH to PDX?
June is the weakest month at 73.7% on time, compared with 89.9% in April. Across the year that is 16 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- PDX to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Portland International (PDX) delay statistics
- United Airlines on IAH to PDX82.3%
- Alaska Airlines on IAH to PDX77.6%
- IAH to ORD, a related route75.1%
- SEA to PDX, a related route82.2%
- IAH to DFW, a related route76.4%
- United Airlines on-time record82.3%
- Alaska Airlines on-time record77.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. IAH to PDX and PDX to IAH are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.