About 1 in 3 UA 5666 flights from Idaho Falls arrived 15+ minutes late, diverted or cancelled over the past year (36%); 0.5% were cancelled. The typical flight landed 2 minutes early.
UA 5666: IDA → DEN
Scheduled to leave Idaho Falls at 4:19 p.m. local time, operated by SkyWest as OO 5666. Over the past year it arrived on time 65% of the time (200 flights), in line with other UA flights on the route at that hour (64%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 30 | 67% |
| Tuesday | 26 | 81% |
| Wednesday | 30 | 57% |
| Thursday | 28 | 54% |
| Friday | 29 | 66% |
| Saturday | 26 | 46% |
| Sunday | 31 | 81% |
Why it was late
All flights IDA → DEN · Connecting off UA 5666? Check the risk
Questions
How often is UA 5666 from IDA to DEN late?
United Airlines 5666 from Idaho Falls, ID to Denver, CO arrived 15 or more minutes late, was diverted or was cancelled on 36% of 200 scheduled flights between September 2025 and August 2026. 0.5% 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.