Route reliability record

DEN→TUL

Denver to Tulsa

Flights: 2,432
Period: July 2025 to June 2026
Distance: 541 mi
Carriers: 4

This route lands a B+, 2 points worse than the national rate of 77.6%. About one flight in four arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 2,432 flights, of which SkyWest Airlines flew 1,129 at 85.4% on time.

SkyWest Airlines is the most reliable of the three carriers covered here at 85.4% on time across 1,129 flights.

On time

76.1%

Arrivals under 15 minutes late, of 2,412 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.78%

National rate is 1.81%

Best carrier

SkyWest

85.4% on time across 1,129 flights

These figures cover 2,432 flights between July 2025 and June 2026. The median arrival is 5 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

Which airline is most reliable on DEN to TUL

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 85.4% of the time; Southwest Airlines manages 64.1%. Sample sizes sit next to every figure, because a two-point gap across 893 flights means less than a ten-point one.

On-time performance by carrier on DEN to TUL
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	1,129	85.4%	69 min	0.62%	A+
Frontier Airlinesthin sample	43	76.7%	74 min	0.00%	B+
United Airlines	367	76.6%	75 min	0.82%	B+
Southwest Airlines	893	64.1%	53 min	1.01%	D

The spread between SkyWest and Southwest is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 more arrivals inside the on-time window.

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am614 flights85.8%
11am–2pm478 flights85.4%
2pm–5pm218 flights66.4%
5pm–8pm629 flights67.0%
8pm–5am493 flights71.0%

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 85.8% of the time, against 66.4% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 629 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 28 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.January best, July worst

July is the worst month at 58.6% on time, 28 points below January, the best at 86.6%. 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. June was the busiest month here, with 228 flights.

Across the week, Saturday is the strongest day at 78.7% on time and Thursday the weakest at 72.5%. 6 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 35,000 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.

Late-arriving aircraft
50%
Carrier
30%
National Airspace System
14%
Extreme weather
6%

50% 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 35,000 reported delay minutes here, that single category outweighs weather by 8 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 35,177 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 85.8% on time here.

Cancellations are rare at 0.78%, 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 actually costs

7.5% 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 are the about an hour kind, which a normal layover absorbs.

The 541 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 79.8% on time across 2,430 flights, 4 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 4 points of difference.

The sample behind these figures is 2,432 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 86.6% on time and July 58.6%, a swing of 28 points. If the dates move at all, move them out of July before you think about anything else. 2,412 completed flights over 12 months sit behind that.

Common questions

DEN to TUL questions

How often is DEN to TUL delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.9% of the 2,432 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on DEN to TUL?

SkyWest Airlines leads at 85.4% on time across 1,129 flights. Southwest Airlines is at the other end on 64.1%, a gap of 21 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on DEN to TUL?

The 8am–11am departure window is the strongest at 85.8% on time. The 2pm–5pm window is the weakest at 66.4%, 19 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are July delays on DEN to TUL?

July is the weakest month at 58.6% on time, compared with 86.6% in January. Across the year that is 28 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. DEN to TUL and TUL to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures