Flight number record
UA 320
United Airlines · Denver to Houston
- Route
- DEN → IAH
- Departs
- 05:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 320, check with United Airlines.
UA 320 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 19 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 364 flights, with a median arrival 16 minutes early.
Set against the rest of the country, UA 320's record is 19 points better than the US average of 77.3%. That gap is worth roughly 194 fewer late arrivals for every thousand flights.
Key figures
On time
96.7%
Arrivals under 15 minutes late, of 363 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.89%
1 hour+ late
0.8%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 16 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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Schedule
When UA 320 flies
UA 320 flies DEN to IAH without a single fixed slot. Its most common scheduled departure was 05:00, used on 267 of 364 flights, with 05:02 (40 flights) next.
- Departs 05:00267 flights73.4%
- Departs 05:0240 flights11.0%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 05:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 320 runs 7 points better at 96.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 320 next to DEN to IAH
Every carrier on DEN to IAH combined arrived on time 79.6% of the time across 4,728 flights, so UA 320 is 17 points ahead of it. United flew 3,894 flights on the same city pair under all its flight numbers, including this one, and those ran 79.7% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 18 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 320thin sample | 364 | 96.7% | 56 min | 0.27% | A+ |
| All United Airlines on DEN–IAH | 3,894 | 79.7% | 63 min | 0.26% | B+ |
| All carriers on DEN–IAH | 4,728 | 79.6% | 62 min | 0.30% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 320 quarter by quarter
Quarter by quarter UA 320 held fairly steady: 100.0% in Jul–Sep 2025, 96.7% in Oct–Dec 2025, 93.2% in Jan–Mar 2026, 96.7% in Apr–Jun 2026 and 100.0% in Jul–Sep 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights100.0%
- Oct–Dec 202592 flights96.7%
- Jan–Mar 202689 flights93.2%
- Apr–Jun 202691 flights96.7%
- Jul–Sep 202662 flights100.0%
Scale runs 85% to 100%.
By weekday, UA 320 ranged from 92.5% on Monday to 100.0% on Tuesday. With about 52 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 320 runs when it is late
UA 320 often beats the schedule: 199 of 363 completed flights, 55%, arrived 15 minutes or more early. Most of the lateness is short. 9 of the 12 late arrivals were under half an hour behind, and 3 reached an hour or more.
- 15+ min early199 flights54.8%
- Within 15 min152 flights41.9%
- 15–29 min late9 flights2.5%
- 30–59 min late0 flights0.0%
- 1–2 hours late2 flights0.6%
- 2+ hours late1 flights0.3%
Scale runs 0% to 100%.
Share of 363 completed flights by arrival against schedule.
Only 13 of 363 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for UA 320
The latest arrival of the period was on 16 March 2026, 4 hours 11 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. Three of the five worst days fell in March 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 16 March 2026 | 4 hours 11 minutes | National Airspace System |
| 5 April 2026 | 1 hour 58 minutes | Carrier |
| 1 June 2026 | 1 hour 46 minutes | Carrier |
| 7 March 2026 | 29 minutes | National Airspace System |
| 15 March 2026 | 28 minutes | National Airspace System |
Delay causes
Why UA 320 runs late
National Airspace System accounts for 51% of the 670 delay minutes carriers reported here, and the remaining four split what is left.
- 51%National Airspace System
- 49%Carrier
The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 325 of the 670 delay minutes reported here. The split is drawn from 670 delay minutes reported on UA 320.
Cancellations are rare at 0.27%, 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 routes
What a delay on this flight costs
Badly late arrivals are rare here: only 0.8% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 861 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 same number turns up on seven other city pairs in the data, including IAH to DFW (50), IAH to BWI (19) and IAH to SMF (18), but none flew often enough under UA 320 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to IAH only.
One caution: this is a thin sample. 364 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 UA 320
For a booking, UA 320 has one of the better records a US domestic flight can show: 96.7% on time and 0.27% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- DEN to IAH, every carrier and departure
- IAH to DEN, the return direction
- United Airlines 1720 on the same route90.1%
- United Airlines 475 on the same route74.1%
- United Airlines 1829 on the same route71.2%
- United Airlines 489 on the same route77.9%
- United Airlines 2419 on the same route78.9%
- Frontier Airlines 2996 on the same route73.9%
- Denver International (DEN) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.