About 1 in 4 UA 645 flights from Denver arrived 15+ minutes late, diverted or cancelled over the past year (26%); 1.2% were cancelled. The typical flight landed 4 minutes early.
UA 645: DEN → FSD
Scheduled to leave Denver at 5:28 p.m. local time. Over the past year it arrived on time 74% of the time (338 flights), in line with other UA flights on the route at that hour (75%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 49 | 67% |
| Tuesday | 48 | 85% |
| Wednesday | 47 | 74% |
| Thursday | 48 | 65% |
| Friday | 49 | 76% |
| Saturday | 48 | 77% |
| Sunday | 49 | 76% |
Why it was late
All flights DEN → FSD · Connecting off UA 645? Check the risk
UA 645: TPA → DEN
Scheduled to leave Tampa at 12:45 p.m. local time. Over the past year it arrived on time 92% of the time (180 flights), in line with other UA flights on the route at that hour (90%). Last seen in the data Aug 10, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 26 | 77% |
| Tuesday | 25 | 96% |
| Wednesday | 25 | 96% |
| Thursday | 26 | 85% |
| Friday | 26 | 92% |
| Saturday | 26 | 96% |
| Sunday | 26 | 100% |
Why it was late
All flights TPA → DEN · Connecting off UA 645? Check the risk
Questions
How often is UA 645 from DEN to FSD late?
United Airlines 645 from Denver, CO to Sioux Falls, SD arrived 15 or more minutes late, was diverted or was cancelled on 26% of 338 scheduled flights between September 2025 and August 2026. 1.2% were cancelled.
How often is UA 645 from TPA to DEN late?
United Airlines 645 from Tampa, FL to Denver, CO arrived 15 or more minutes late, was diverted or was cancelled on 8% of 180 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.