Flight number record
UA 644
United Airlines · Denver to Portland
- Route
- DEN → PDX
- Departs
- 11:50
- Flights
- 312
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 644, check with United Airlines.
UA 644 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 6 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 312 flights, with a median arrival 5 minutes early.
Set against the rest of the country, UA 644's record is 6 points better than the US average of 77.6%. That gap is worth roughly 64 fewer late arrivals for every thousand flights.
Key figures
On time
84.0%
Arrivals under 15 minutes late, of 312 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
1 hour+ late
3.5%
National rate is 8.1%
These figures cover 312 flights between July 2025 and June 2026. The median arrival is 5 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.
Schedule
When UA 644 flies
UA 644 flies DEN to PDX without a single fixed slot. Its most common scheduled departure was 11:50, used on 82 of 312 flights, with 11:20 (68 flights) and 11:18 (49 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 11:5082 flights26.3%
- Departs 11:2068 flights21.8%
- Departs 11:1849 flights15.7%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 11:50 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and UA 644 runs 5 points better at 84.0%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
UA 644 next to DEN to PDX
Every carrier on DEN to PDX combined arrived on time 73.9% of the time across 4,289 flights, so UA 644 is 10 points ahead of it. United flew 1,821 flights on the same city pair under all its flight numbers, including this one, and those ran 81.7% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 5 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 644thin sample | 312 | 84.0% | 47 min | 0.00% | B+ |
| All United Airlines on DEN–PDX | 1,821 | 81.7% | 60 min | 0.44% | B+ |
| All carriers on DEN–PDX | 4,289 | 73.9% | 53 min | 0.44% | C+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 644 quarter by quarter
Quarter by quarter UA 644 held fairly steady: 85.9% in Jul–Sep 2025, 84.6% in Oct–Dec 2025, 83.3% in Jan–Mar 2026 and 82.4% in Apr–Jun 2026. A spread of 4 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202592 flights85.9%
- Oct–Dec 202539 flights84.6%
- Jan–Mar 202690 flights83.3%
- Apr–Jun 202691 flights82.4%
Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, UA 644 ranged from 77.3% on Wednesday to 88.9% on Friday. With about 45 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why UA 644 runs late
One category carries most of the weight here. Carrier accounts for 42% of the 2,326 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 42%Carrier
- 32%Late-arriving aircraft
- 24%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 985 of the 2,326 delay minutes reported here. The split is drawn from 2,326 delay minutes reported on UA 644.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are 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 3.5% land an hour or more behind schedule, against 8.1% 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 991 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 same number turns up on ten other city pairs in the data, including DFW to DEN (62), BNA to IAH (52) and PDX to SFO (38), but none flew often enough under UA 644 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to PDX only.
One caution: this is a thin sample. 312 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 644
For a booking, read UA 644 as 84.0% on time with 0.00% cancelled over 312 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to PDX, every carrier and departure
- PDX to DEN, the return direction
- United Airlines 498 on the same route76.3%
- United Airlines 1247 on the same route88.1%
- United Airlines 1337 on the same route82.3%
- Denver International (DEN) delay statistics
- Portland International (PDX) 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
- Why the first flight of the morning is statistically safest
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.