Route reliability record

DEN→ATL

Denver to Atlanta

Flights: 5,603
Period: September 2025 to August 2026
Distance: 1,199 mi
Carriers: 4

This route lands a B+, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 5,603 DEN to ATL flights, of which Delta Air Lines flew 2,807 at 85.8% on time.

Best time to fly DEN to ATL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 92.6% of the time and Wednesday flights 81.8%, against 78.6% for the route overall.

Delta Air Lines is the most reliable of the four carriers covered here at 85.8% on time across 2,807 flights.

On time

78.6%

Arrivals under 15 minutes late, of 5,521 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.93%

National rate is 1.89%

Best carrier

Delta

85.8% on time across 2,807 flights

These figures cover 5,603 flights between September 2025 and August 2026. The median arrival is 6 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.

Carrier by carrier

Which airline is most reliable on DEN to ATL

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 85.8% of the time; Southwest Airlines manages 62.4%. Sample sizes sit next to every figure, because a two-point gap across 1,072 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	2,807	85.8%	61 min	1.18%	A
United Airlines	923	77.9%	61 min	0.33%	B+
Frontier Airlines	801	75.5%	62 min	0.87%	B+
Southwest Airlines	1,072	62.4%	51 min	0.84%	D+

The spread between Delta and Southwest is 23 points, wide enough that it should decide the booking. On a hundred trips that is 23 more arrivals inside the on-time window.

Flight by flight

Flights on DEN to ATL

The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.

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.

Best ways to make this trip

The most reliable ways to fly Denver to Atlanta

Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.

Most reliable ways to fly from DEN to ATL
Option	Airline	Success	On time	Cancelled	Best departure	Most punctual flight
1. DEN → ATLDenver to Atlanta	Delta Air Lines	84.8%	85.8%	1.18%	5am–8am, Wed	DL 341 06:00
2. DEN → ATLDenver to Atlanta	United Airlines	77.6%	77.9%	0.33%	8am–11am, Tue	UA 1305 17:48
3. DEN → ATLDenver to Atlanta	Frontier Airlines	74.8%	75.5%	0.87%	5am–8am, Wed	F9 3294 06:30
4. DEN → ATLDenver to Atlanta	Southwest Airlines	61.9%	62.4%	0.84%	5am–8am, Sat	—

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

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 33 points, against 23 points between the best and worst carrier.

5am–8am928 flights92.6%
8am–11am1,167 flights80.2%
11am–2pm1,146 flights79.3%
2pm–5pm1,146 flights75.4%
5pm–8pm625 flights59.5%
8pm–5am591 flights78.1%

Scale runs 50% to 100%.

The 5pm–8pm window is where this operation falls apart: 59.5% on time, against 92.6% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 1,167 flights scheduled in it.

Explore

Filter DEN to ATL by airline, time, month and day

Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.

On DEN to ATL, the best departure window is 5am–8am at 92.6% on time and the worst is 5pm–8pm at 59.5%, a wide gap of 33.1 points. All US flights leaving 5am–8am ran 89.3%.

5–8am92.6%
8–11am80.2%
11am–2pm79.3%
2–5pm75.4%
5–8pm59.5%
8pm–5am78.1%

best all US flightsScale 50% to 95%.

Across the year

When delays peak on this route

This route's year swings by 27 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.November best, July worst

July is the worst month at 63.2% on time, 27 points below November, the best at 90.5%. 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. July was the busiest month here, with 531 flights.

Across the week, Wednesday is the strongest day at 81.8% on time and Sunday the weakest at 75.5%, a spread of 6 points.

Delay causes

Why this route gets delayed

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 69,000 reported delay minutes.

Late-arriving aircraft
40%
Carrier
39%
National Airspace System
18%
Extreme weather
3%
Security
0%

40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 69,000 reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 68,560 reported delay minutes.

The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 26,000 of the 69,000 delay minutes reported here.

Cancellations sit at 0.93% against a national 1.89%, which is ordinary. Diversions add another 0.54%.

Connections and stage length

What a delay here actually costs

6.1% 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 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.

The return leg runs 78.0% on time across 5,594 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 5,603 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.

Work out the risk of missing a connection in ATL after this flight

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 90.5% on time and July 63.2%, a swing of 27 points. If the dates move at all, move them out of July before you think about anything else. 5,521 completed flights over 12 months sit behind that.

Common questions

DEN to ATL questions

How often is DEN to ATL delayed?

About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.4% of the 5,603 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on DEN to ATL?

Delta Air Lines leads at 85.8% on time across 2,807 flights. Southwest Airlines is at the other end on 62.4%, a gap of 23 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 ATL?

The 5am–8am departure window is the strongest at 92.6% on time. The 5pm–8pm window is the weakest at 59.5%, 33 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 ATL?

July is the weakest month at 63.2% on time, compared with 90.5% in November. Across the year that is 27 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 ATL and ATL to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Embed DEN to ATL’s on-time badge on your site

Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.

<iframe src="https://delayatlas.com/embed/route/den-atl" width="320" height="132" style="border:0;max-width:100%" loading="lazy" title="DEN to ATL on-time record"></iframe>
<p style="font:12px/1.4 sans-serif;margin:4px 0 0">DEN to ATL flight delay statistics from <a href="https://delayatlas.com/routes/den-to-atl">DelayAtlas</a></p>

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.