Carrier route record

DLDEN→ATL

Delta Air Lines · Denver to Atlanta

Flights: 2,805
Period: July 2025 to June 2026
Share of route: 50%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on DEN to ATL earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 2,805 flights. The strongest carrier on the route with a full sample, Frontier Airlines, flew 744 at 78.9% on time.

Set against the rest of the country, Delta's DEN to ATL record is 9 points better than the US average of 77.6%. That gap is worth roughly 87 fewer late arrivals for every thousand flights.

On time

86.3%

Arrivals under 15 minutes late, of 2,767 completed flights

Avg delay

71 min

Across delayed arrivals only, not all flights

Cancelled

1.07%

National rate is 1.81%

Whole route

80.0%

Every carrier on DEN to ATL, 5,596 flights

These figures cover 2,805 flights between July 2025 and June 2026. The median arrival is 11 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

Delta against every carrier on DEN to ATL

Delta flew 2,805 of the 5,596 flights on DEN to ATL, most of the route. Its 86.3% on time is 6 points better than the route as a whole, which runs 80.0%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Delta at 86.3% to Southwest at 66.3%.

The choice of carrier is not cosmetic here. Frontier Airlines arrives on time 78.9% of the time; Southwest Airlines manages 66.3%. Sample sizes sit next to every figure, because a two-point gap across 1,080 flights means less than a ten-point one.

On-time performance by carrier on DEN to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)	2,805	86.3%	71 min	1.07%	A
Frontier Airlines	744	78.9%	61 min	0.81%	B+
United Airlines	967	78.0%	64 min	0.31%	B+
Southwest Airlines	1,080	66.3%	54 min	0.83%	C+

The spread between Frontier and Southwest is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.

Flight by flight

Delta flight numbers on DEN to ATL

Departure window

When Delta 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 2,805 flights.

5am–8am730 flights92.2%
8am–11am447 flights84.2%
11am–2pm640 flights83.0%
2pm–5pm783 flights84.5%
5pm–8pm12 flights—
8pm–5am193 flights91.0%

Scale runs 75% to 100%. 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 83.0% on time against 92.2% for 5am–8am. 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 783 flights scheduled in it.

Across the year

Delta on DEN to ATL through the year

Darker means more delays. Figures are on-time percentages.April best, December worst

December is the weak month at 75.0% on time, against 94.0% in April. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 257 flights.

Across the week, Wednesday is the strongest day at 89.7% on time and Sunday the weakest at 83.9%. 6 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 42% of the 27,000 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.

Carrier
42%
Late-arriving aircraft
39%
National Airspace System
13%
Extreme weather
6%

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 27,000 reported delay minutes here, that single category outweighs weather by 7 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 26,636 reported delay minutes.

The largest share of delay minutes, 42%, 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 11,000 of the 27,000 delay minutes reported here.

Cancellations sit at 1.07% against a national 1.81%, which is ordinary. Diversions add another 0.29%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.3% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 1,199 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 78.1% on time across 2,805 flights, 8 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 8 points of difference.

The sample behind these figures is 2,805 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 Delta on DEN to ATL

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 94.0% on time and December 75.0%, a swing of 19 points. If the dates move at all, move them out of December before you think about anything else. 2,767 completed flights over 12 months sit behind that.

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.

Key figures