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DelayAtlas

Carrier route record

DLATLPHL

Delta Air Lines · Atlanta to Philadelphia

Flights
3,028
Period
July 2025 to June 2026
Share of route
53%
Carriers
6
BGRADE

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

Delta on ATL to PHL lands a B, 2 points worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 3,028 flights. The strongest carrier on the route with a full sample, PSA Airlines, flew 834 at 81.5% on time.

PSA Airlines is the most reliable of the three carriers covered here at 81.5% on time across 834 flights.

Key figures

On time

76.1%

Arrivals under 15 minutes late, of 2,951 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

2.48%

National rate is 1.81%

Whole route

74.9%

Every carrier on ATL to PHL, 5,713 flights

These figures cover 3,028 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Delta against every carrier on ATL to PHL

Delta flew 3,028 of the 5,713 flights on ATL to PHL, most of the route. Its 76.1% on time is about level with the route as a whole at 74.9%. Ranked by on-time rate it is number four of six carriers on the route, where the range runs from Republic at 90.7% to Frontier at 62.4%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. PSA Airlines arrives on time 81.5% of the time; Frontier Airlines manages 62.4%. Sample sizes sit next to every figure, because a two-point gap across 1,010 flights means less than a ten-point one.

On-time performance by carrier on ATL to PHL
AirlineFlightsOn timeAvg delayCancelledGrade
Republic Airwaysthin sample15690.7%95 min3.85%A−
PSA Airlines83481.5%98 min4.56%B−
American Airlines59278.1%120 min2.03%B
Delta Air Lines (this page)3,02876.1%52 min2.48%B
Spirit Airlinesthin sample9365.2%72 min1.08%C
Frontier Airlines1,01062.4%84 min2.97%D

PSA Airlines cancels 4.6% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Flight by flight

Delta flight numbers on ATL to PHL

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 19 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am290 flights85.7%
  • 8am–11am367 flights86.5%
  • 11am–2pm451 flights84.0%
  • 2pm–5pm877 flights70.4%
  • 5pm–8pm381 flights64.6%
  • 8pm–5am662 flights74.8%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 64.6% on time, against 86.5% for the 8am–11am 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 2pm–5pm window is the busiest, with 877 flights scheduled in it.

Across the year

Delta on ATL to PHL through the year

On-time rate by calendar month80J76F68M79A81M78J60J77A84S79O85N71D
Darker means more delays. Figures are on-time percentages.November best, July worst

July is the worst month at 59.7% on time, 25 points below November, the best at 84.8%. 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 283 flights.

Across the week, Saturday is the strongest day at 81.6% on time and Sunday the weakest at 70.3%. 11 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week70.5Mon78.6Tue80.5Wed72.6Thu79.6Fri81.6Sat70.3Sun
Monday: 70.5 percent on time. Tuesday: 78.6 percent on time. Wednesday: 80.5 percent on time. Thursday: 72.6 percent on time. Friday: 79.6 percent on time. Saturday: 81.6 percent on time. Sunday: 70.3 percent on time

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 45% of the 36,000 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
    45%
  • National Airspace System
    30%
  • Late-arriving aircraft
    21%
  • Extreme weather
    4%
  • Security
    0%

The largest share of delay minutes, 45%, 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 16,000 of the 36,000 delay minutes reported here. The split is drawn from 36,450 reported delay minutes.

Cancellations sit at 2.48% against a national 1.81%, which is ordinary. Diversions add another 0.07%.

Connections and stage length

What a delay here costs

6.1% 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 roughly 50 minutes, which a normal layover absorbs.

The 666 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 84.9% on time across 3,029 flights, 9 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 9 points of difference.

The sample behind these figures is 3,028 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 ATL to PHL

Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 84.8% on time and July 59.7%, a swing of 25 points. If the dates move at all, move them out of July before you think about anything else. 2,951 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.