Carrier route record
UAJAX→DEN
United Airlines · Jacksonville to Denver
- Flights
- 617
- Period
- July 2025 to June 2026
- Share of route
- 62%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on JAX to DEN earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 617 flights, with a median arrival 9 minutes early.
Set against the rest of the country, United's JAX to DEN record is 11 points better than the US average of 77.6%. That gap is worth roughly 110 fewer late arrivals for every thousand flights.
Key figures
On time
88.6%
Arrivals under 15 minutes late, of 614 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
0.16%
National rate is 1.81%
Whole route
83.6%
Every carrier on JAX to DEN, 995 flights
These figures cover 617 flights between July 2025 and June 2026. The median arrival is 9 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.
Carrier by carrier
United against every carrier on JAX to DEN
United flew 617 of the 995 flights on JAX to DEN, most of the route. Its 88.6% on time is 5 points better than the route as a whole, which runs 83.6%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 88.6% to Southwest at 75.5%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 617 | 88.6% | 94 min | 0.16% | A+ |
| Southwest Airlines | 378 | 75.5% | 54 min | 0.26% | B+ |
Departure window
When United runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 617 flights.
- 5am–8am—
- 8am–11am350 flights92.6%
- 11am–2pm—
- 2pm–5pm267 flights83.3%
- 5pm–8pm—
- 8pm–5am—
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 92.6% of the time, against 83.3% for the afternoon window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 350 flights scheduled in it.
Across the year
United on JAX to DEN through the year
June is the worst month at 80.4% on time, 18 points below November, the best at 98.3%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 62 flights.
Across the week, Wednesday is the strongest day at 94.8% on time and Sunday the weakest at 80.4%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. Carrier accounts for 47% of the 6,556 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 47%Carrier
- 30%Late-arriving aircraft
- 20%National Airspace System
- 4%Extreme weather
The largest share of delay minutes, 47%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 3,049 of the 6,556 delay minutes reported here. The split is drawn from 6,556 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.6% on time here.
Cancellations are rare at 0.16%, below the national 1.81% 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 stage length
What a delay here costs
5.2% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
The 1,446 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 81.2% on time across 617 flights, 7 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 7 points of difference.
One caution: this is a thin sample. 617 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 United on JAX to DEN
Put together: treat all of this as provisional. 617 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 88.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 614 completed flights over 12 months sit behind that.
Related
Where to go next
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.