Carrier route record
WNDEN→JAX
Southwest Airlines · Denver to Jacksonville
- Flights
- 378
- Period
- July 2025 to June 2026
- Share of route
- 38%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to JAX sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 378 flights, with a median arrival 6 minutes late.
The national on-time rate over the same period is 77.6%, so Southwest on DEN to JAX runs 9 points behind the country as a whole. Across a thousand flights that is about 92 extra late arrivals.
Key figures
On time
68.4%
Arrivals under 15 minutes late, of 377 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
Whole route
76.3%
Every carrier on DEN to JAX, 995 flights
These figures cover 378 flights between July 2025 and June 2026. Beyond the headline rate, 8.0% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Southwest against every carrier on DEN to JAX
Southwest flew 378 of the 995 flights on DEN to JAX, about 38% of it. Its 68.4% on time is 8 points worse than the route as a whole, which runs 76.3%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from United at 81.2% to Southwest at 68.4%.
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 | 617 | 81.2% | 63 min | 0.00% | B+ |
| Southwest Airlines (this page) | 378 | 68.4% | 51 min | 0.00% | C+ |
Departure window
When Southwest 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 378 flights.
- 5am–8am—
- 8am–11am19 flights—
- 11am–2pm143 flights65.7%
- 2pm–5pm194 flights71.0%
- 5pm–8pm17 flights—
- 8pm–5am5 flights—
Scale runs 55% to 75%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 65.7% on time against 71.0% for 2pm–5pm. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 2pm–5pm window is the busiest, with 194 flights scheduled in it.
Across the year
Southwest on DEN to JAX through the year
June is the worst month at 38.2% on time, 52 points below November, the best at 90.6%. 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. March was the busiest month here, with 35 flights.
Across the week, Friday is the strongest day at 76.5% on time and Wednesday the weakest at 61.5%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 6,042 reported delay minutes.
- 41%Carrier
- 39%Late-arriving aircraft
- 19%National Airspace System
- 1%Extreme weather
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 6,042 reported delay minutes here, that single category outweighs weather by 28 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 6,042 reported delay minutes.
The largest share of delay minutes, 41%, 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 2,470 of the 6,042 delay minutes reported here.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
8.0% 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 about 50 minutes, 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 75.5% on time across 378 flights, 7 points above 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. 378 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 Southwest on DEN to JAX
Put together: treat all of this as provisional. 378 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 68.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 377 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.