About 1 in 6 UA 644 flights from Denver arrived 15+ minutes late, diverted or cancelled over the past year (16%); 0.0% were cancelled. The typical flight landed 5 minutes early.
UA 644: DEN → PDX
Scheduled to leave Denver at 11:50 a.m. local time. Over the past year it arrived on time 84% of the time (312 flights), in line with other UA flights on the route at that hour (82%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 45 | 91% |
| Tuesday | 44 | 86% |
| Wednesday | 44 | 77% |
| Thursday | 45 | 82% |
| Friday | 45 | 87% |
| Saturday | 45 | 80% |
| Sunday | 44 | 86% |
Why it was late
All flights DEN → PDX · Connecting off UA 644? Check the risk
UA 644: DFW → DEN
Scheduled to leave Dallas at 8:45 a.m. local time. Over the past year it arrived on time 85% of the time (124 flights), better than other UA flights on the route at that hour (81%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 19 | — |
| Tuesday | 18 | — |
| Wednesday | 18 | — |
| Thursday | 17 | — |
| Friday | 17 | — |
| Saturday | 17 | — |
| Sunday | 18 | — |
Why it was late
All flights DFW → DEN · Connecting off UA 644? Check the risk
Questions
How often is UA 644 from DEN to PDX late?
United Airlines 644 from Denver, CO to Portland, OR arrived 15 or more minutes late, was diverted or was cancelled on 16% of 312 scheduled flights between September 2025 and August 2026. 0.0% were cancelled.
How often is UA 644 from DFW to DEN late?
United Airlines 644 from Dallas/Fort Worth, TX to Denver, CO arrived 15 or more minutes late, was diverted or was cancelled on 15% of 124 scheduled flights between September 2025 and August 2026. 0.0% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check United Airlines for today's flight. Method.