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Route · STL → PHL · 2020–2025 BTS data

St. Louis to Philadelphia

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), STL to PHL (St. Louis to Philadelphia) ranks #1468 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

83.5%
On-time
+4.5 pts
vs US avg
82 min
Delay when late
8,317
Flights
#1468 of 4927
Corpus placement

Cancelled

1.9%

Best Month

May 2025 89%

Worst Month

Jul 2025 68%

Distance

814 mi

Carriers

29

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 148 32 1 0 YX,OH,WN,AA
Nov 2025 162 25 1 0 OH,AA,WN,YX
Oct 2025 147 26 0 1 AA,WN,YX
Sep 2025 132 24 0 0 WN,AA
Aug 2025 142 29 0 1 AA,WN,YX
Jul 2025 135 43 5 1 AA,WN,YX
Jun 2025 132 34 3 0 AA,OH,WN,YX
May 2025 118 13 3 0 AA,OH,WN
Apr 2025 115 16 1 0 OH,WN,AA
Mar 2025 105 17 2 0 OH,WN
Feb 2025 78 14 3 0 OH,WN,YX
Jan 2025 91 15 10 1 OH,WN,YX
Dec 2024 133 30 0 0 AA,OH,WN,YX
Nov 2024 129 18 1 0 WN,YX,OH,AA
Oct 2024 187 22 0 0 WN,YX,AA,OH
Sep 2024 172 20 0 0 WN,YX,AA
Aug 2024 201 48 10 1 AA,F9,WN,YX
Jul 2024 198 53 11 2 AA,F9,WN,YX
Jun 2024 186 37 3 1 AA,F9,WN,YX
May 2024 120 32 2 0 AA,F9,WN
Apr 2024 86 15 0 0 AA,WN
Mar 2024 80 14 0 0 AA,WN
Feb 2024 62 9 0 0 AA,WN
Jan 2024 72 17 2 0 AA,WN

STL–PHL seasonal on-time pattern

Best: April (87.8%) · weakest: July (77.3%)

75%80%85%90% JanFebMarAprMayJunJulAugSepOctNovDec 79.2%

Strongest calendar month

April

87.8% on-time · ~116 flights/mo

Busiest calendar month

August

~140 flights/mo avg

Weakest calendar month

July

77.3% on-time · ~136 flights/mo

Cancellation Rate

1.9%

58 of 3,131 flights

Diversion Rate

0.3%

8 of 3,131 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

STL - St. Louis

Full on-time, delay-cause, and seasonal performance for St. Louis, MO.

STL on-time profile

PHL - Philadelphia

Full on-time, delay-cause, and seasonal performance for Philadelphia, PA.

PHL on-time profile

Compare the two airports

See STL and PHL side by side on delays, cancellations, and reliability.

Compare STL vs PHL

Origin-hub reliability standing

Mid-pack among STL departures

From STL, this corridor sits with 45 other 75–85% on-time routes out of 51 tracked departures, not the hub's reliability leaders (5 at ≥85%) and not the softest ( 1 below 75%). Destination: Philadelphia · fleet on-time rank #1775 of 4927.

What the Data Says About STL to PHL

Bureau of Transportation Statistics records show St. Louis to Philadelphia (STL to PHL) running a 83.5% on-time rate over 8,317 tracked flights, on the stronger end of a typical domestic pairing. When flights do run late, the average delay is 82.2 minutes. The 814-mile corridor is served by 29 carriers, and over the last 24 months 1.9% of 3,131 flights were cancelled, 0.3% diverted.

The monthly split is wide on this route: May 2025 posted the strongest performance at 89% on-time, while Jul 2025 came in at just 68% - a 21-point swing worth factoring into travel timing.

On the multi-year calendar, STL–PHL peaks in April at 87.8% on-time while August carries the heaviest traffic (~140 flights per month) ; the softest month is July at 77.3%, a 10.5-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does STL to PHL rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, STL to PHL ranks #1468 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from STL to PHL? ▼
Flights from St. Louis to Philadelphia have a 83.5% on-time rate based on 8,317 flights. The average delay is 82.2 minutes. The best recent month was May 2025 with 89% on-time.
What is the cancellation rate for STL to PHL? ▼
Over the last 24 months, 1.9% of flights on this route were cancelled (58 of 3,131 flights) and 0.3% were diverted.
How far is the flight from STL to PHL? ▼
The flight distance from St. Louis (STL) to Philadelphia (PHL) is approximately 814 miles. This route is served by 29 carriers.
When is the best time to fly from STL to PHL? ▼
The best recent month for on-time performance was May 2025 (89% on-time). The worst was Jul 2025 (68% on-time). Consider booking during months with historically better performance.

Airports on this route

STL Airport

St. Louis
PHL Airport

Philadelphia
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using STL–PHL data

STL–PHL runs 4.5 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare STL and PHL airport profiles: delay causes and top routes differ even on the same corridor. STL airport
  • If your dates flex, April (87.8% on-time) beats July (77.3%) on this corridor. Seasonal chart
  • 4 other routes post a similar 83.5% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.