About 1 in 3 UA 4638 flights from Chicago arrived 15+ minutes late, diverted or cancelled over the past year (39%); 4.1% were cancelled. The typical flight landed 5 minutes late.
UA 4638: ORD → COS
Scheduled to leave Chicago at 7:45 p.m. local time, operated by SkyWest as OO 4638. Over the past year it arrived on time 61% of the time (246 flights), in line with other UA flights on the route at that hour (61%). Last seen in the data Aug 31, 2026.
Usually United Airlines's last flight of the day from Chicago to Colorado Springs (96% of days). United Airlines's last ORD–COS flight was cancelled 3.3% of the time, against 0.7% for its earlier ones. If it's cancelled, the next United Airlines flight is usually around 9:06 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 38 | 50% |
| Tuesday | 36 | 69% |
| Wednesday | 34 | 59% |
| Thursday | 34 | 65% |
| Friday | 35 | 49% |
| Saturday | 32 | 69% |
| Sunday | 37 | 65% |
Why it was late
All flights ORD → COS · Connecting off UA 4638? Check the risk
Questions
How often is UA 4638 from ORD to COS late?
United Airlines 4638 from Chicago, IL to Colorado Springs, CO arrived 15 or more minutes late, was diverted or was cancelled on 39% of 246 scheduled flights between September 2025 and August 2026. 4.1% 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.