Flight number record
UA 663
United Airlines · Denver to Medford
- Route
- DEN → MFR
- Departs
- 19:20
- Flights
- 339
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 663, check with United Airlines.
UA 663 lands a B+, level with the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 339 flights, with a median arrival 2 minutes early.
Key figures
On time
77.9%
Arrivals under 15 minutes late, of 335 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.59%
National rate is 1.89%
1 hour+ late
6.0%
National rate is 8.3%
These figures cover 339 flights between September 2025 and August 2026. The median arrival is 2 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When UA 663 flies
UA 663 flies DEN to MFR without a single fixed slot. Its most common scheduled departure was 19:20, used on 71 of 339 flights, with 19:30 (63 flights) and 19:10 (37 flights) next.
- Departs 19:2071 flights20.9%
- Departs 19:3063 flights18.6%
- Departs 19:1037 flights10.9%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 19:20 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and UA 663 runs 10 points better at 77.9%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
UA 663 next to DEN to MFR
Every carrier on DEN to MFR combined arrived on time 77.1% of the time across 730 flights, so UA 663 is about level with it. United flew 574 flights on the same city pair under all its flight numbers, including this one, and those ran 76.8% on time. Across its whole network United Airlines managed 78.8%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 663thin sample | 339 | 77.9% | 64 min | 0.59% | B+ |
| All United Airlines on DEN–MFR | 574 | 76.8% | 53 min | 0.35% | B+ |
| All carriers on DEN–MFR | 730 | 77.1% | 54 min | 0.27% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 663 quarter by quarter
UA 663 did not run the same all year. Its best quarter was Jan–Mar 2026 at 89.2% on time and its weakest Jul–Sep 2026 at 56.9%, a swing of 32 points on roughly 68 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights86.7%
- Oct–Dec 202591 flights85.7%
- Jan–Mar 202666 flights89.2%
- Apr–Jun 202691 flights72.5%
- Jul–Sep 202661 flights56.9%
Scale runs 50% to 95%.
By weekday, UA 663 did best on Friday at 85.1% on time and worst on Sunday at 71.4%. Each day rests on about 48 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 663 runs when it is late
The 74 late arrivals split 22 under half an hour, 32 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early64 flights19.1%
- Within 15 min197 flights58.8%
- 15–29 min late22 flights6.6%
- 30–59 min late32 flights9.6%
- 1–2 hours late9 flights2.7%
- 2+ hours late11 flights3.3%
Scale runs 0% to 100%.
Share of 335 completed flights by arrival against schedule.
26 of 89 late departures made up the time and arrived on time, 29% of them. 11 flights left on time and still arrived late.
The worst days
Worst days for UA 663
The latest arrival of the period was on 22 May 2026, 4 hours 51 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 May 2026 | 4 hours 51 minutes | Late-arriving aircraft |
| 22 July 2026 | 3 hours 55 minutes | Late-arriving aircraft |
| 3 August 2026 | 3 hours 54 minutes | Late-arriving aircraft |
| 31 May 2026 | 3 hours 26 minutes | Late-arriving aircraft |
| 26 August 2026 | 3 hours 12 minutes | Late-arriving aircraft |
Delay causes
Why UA 663 runs late
Late-arriving aircraft accounts for 70% of the 4,705 delay minutes carriers reported here, and the remaining four split what is left.
- 70%Late-arriving aircraft
- 19%Carrier
- 9%National Airspace System
- 2%Extreme weather
70% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,705 reported delay minutes here, that single category outweighs weather by 43 to one. The split is drawn from 4,705 delay minutes reported on UA 663.
Cancellations are rare at 0.59%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
6.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 964 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.
The same number turns up on seven other city pairs in the data, including MCO to EWR (47), EWR to DEN (47) and TPA to DEN (36), but none flew often enough under UA 663 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to MFR only.
One caution: this is a thin sample. 339 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 663
For a booking, read UA 663 as 77.9% on time with 0.59% cancelled over 339 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to MFR, every carrier and departure
- MFR to DEN, the return direction
- Denver International (DEN) 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.