Route on-time record
PHL to STL: most on-time flights and the best time to fly
Philadelphia (Philadelphia International Airport) to St Louis (St. Louis Lambert International Airport). 1,576 nonstop flights in Jun 2025 to May 2026, 76% arrived within 15 minutes and 1.5% were cancelled. The most reliable flight number was Southwest 4401 at 6:20 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
PHL → STL
Philadelphia to St Louis: 1,576 nonstop flights a year
On time (12 months)
76%
Cancelled
1.5%
avg delay 19 min
Best time to leave
Before 9 AM
89% on time vs 63% 6 to 9 PM
Most reliable airline
Southwest
77% chance on time
Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · Southwest 4401
6:20 AM → 7:45 AM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31.
91%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 1 min
- Arrived on time 100% of the time (24 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 89% on time; 6 to 9 PM: 63%).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 24 flights
Find Southwest 4401 fares Opens this date on Aviasales#2 · Southwest 4952
6:10 AM → 7:35 AM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31.
88%
chance on time
- On time (history)
- 92%
- Cancelled
- 0.0%
- Avg arrival delay
- 2 min
- Arrived on time 92% of the time (38 flights, Jun 2025 to May 2026).
- Never cancelled in 38 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 89% on time; 6 to 9 PM: 63%).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 38 flights
Find Southwest 4952 fares Opens this date on Aviasales#3 · American 2720
9:01 AM → 10:37 AM2h 36m nonstop
Local times, typical schedule. Last flown 2026-05-31.
81%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 1 min
- Arrived on time 100% of the time (8 flights, Jun 2025 to May 2026).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 8 flights
Find American 2720 fares Opens this date on Aviasales#4 · American 3130
11:06 AM → 12:48 PM2h 42m nonstop
Local times, typical schedule. Last flown 2026-05-20.
81%
chance on time
- On time (history)
- 89%
- Cancelled
- 0.0%
- Avg arrival delay
- 7 min
- Arrived on time 89% of the time (37 flights, Jun 2025 to May 2026).
- Never cancelled in 38 scheduled flights.
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 37 flights
Find American 3130 fares Opens this date on Aviasales#5 · Southwest 3725
12:20 PM → 1:45 PM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-29.
70%
chance on time
- On time (history)
- 65%
- Cancelled
- 0.0%
- Avg arrival delay
- 27 min
- Arrived on time 65% of the time (23 flights, Jun 2025 to May 2026).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 23 flights
Find Southwest 3725 fares Opens this date on Aviasales#6 · American 1368
5:44 PM → 7:29 PM2h 45m nonstop
Local times, typical schedule. Last flown 2026-05-31.
69%
chance on time
- On time (history)
- 69%
- Cancelled
- 2.3%
- Avg arrival delay
- 24 min
- Arrived on time 69% of the time (167 flights, Jun 2025 to May 2026).
- Departs inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
Moderate track record · 167 flights
Find American 1368 fares Opens this date on Aviasales#7 · Southwest 668
7:10 PM → 8:50 PM2h 40m nonstop
Local times, typical schedule. Last flown 2026-05-31.
67%
chance on time
- On time (history)
- 67%
- Cancelled
- 0.0%
- Avg arrival delay
- 23 min
- Arrived on time 67% of the time (46 flights, Jun 2025 to May 2026).
- Never cancelled in 46 scheduled flights.
- Leaves in this route's least on-time window (6 to 9 PM: 63% on time; Before 9 AM: 89%).
- Departs inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 46 flights
Find Southwest 668 fares Opens this date on Aviasales#8 · American 2714
3:21 PM → 4:59 PM2h 38m nonstop
Local times, typical schedule. Last flown 2026-05-31.
65%
chance on time
- On time (history)
- 80%
- Cancelled
- 0.0%
- Avg arrival delay
- 15 min
- Arrived on time 80% of the time (10 flights, Jun 2025 to May 2026).
- Departs inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 10 flights
Find American 2714 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines77%
724 flights · 77% on time as flown · 0.5% cancel
- American Airlines72%
618 flights · 72% on time as flown · 1.3% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM89%
341 flights · avg delay 10 min
- 9 AM to noon84%
297 flights · avg delay 12 min
- Noon to 3 PM79%
180 flights · avg delay 14 min
- 3 to 6 PM65%
212 flights · avg delay 28 min
- 6 to 9 PM63%
470 flights · avg delay 27 min
- After 9 PM80%
76 flights · avg delay 16 min
Best day: Tuesday (82%). Worst: Thursday (73%).
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Late-arriving aircraft46%
- Airline (crew, maintenance, boarding)29%
- Air traffic control and airport volume19%
- Severe weather5%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
PHL to STL questions
- What time of day is best to fly PHL to STL?
- Before 9 AM: 89% of flights arrived on time, against 63% for departures 6 to 9 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
- Which airline is most on time from PHL to STL?
- Southwest, with a season-adjusted 77% chance of operating and arriving on time over 724 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on PHL to STL?
- July (65% on time); the best was October (87%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from PHL
- STL to PHL (return)
- PHL to ATL 78%
- PHL to MCO 72%
- PHL to BOS 75%
- PHL to ORD 72%
- PHL to CLT 80%
- PHL to DFW 77%
- PHL to FLL 72%
- PHL to MIA 77%
- PHL to DEN 76%
- PHL to DTW 80%
- PHL to BNA 75%
- PHL to TPA 73%
Most on-time flights from PHL on every route →
Live status: FAA delays and ground stops