Route on-time record
BWI to STL: most on-time flights and the best time to fly
Baltimore (Baltimore/Washington International Thurgood Marshall Airport) to St Louis (St. Louis Lambert International Airport). 1,283 nonstop flights in Jun 2025 to May 2026, 83% arrived within 15 minutes and 1.2% were cancelled. The most reliable flight number was Southwest 1333 at 6:25 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
BWI → STL
Baltimore to St Louis: 1,283 nonstop flights a year
On time (12 months)
83%
Cancelled
1.2%
avg delay 12 min
Best time to leave
Before 9 AM
94% on time vs 69% 6 to 9 PM
Most reliable airline
Southwest
82% 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 1333
6:25 AM → 7:45 AM2h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31.
92%
chance on time
- On time (history)
- 94%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 94% of the time (54 flights, Jun 2025 to May 2026).
- Never cancelled in 54 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; 6 to 9 PM: 69%).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
Limited track record · 54 flights
Find Southwest 1333 fares Opens this date on Aviasales#2 · Southwest 3191
6:15 AM → 7:45 AM2h 30m nonstop
Local times, typical schedule. Last flown 2026-04-06.
90%
chance on time
- On time (history)
- 91%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 91% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; 6 to 9 PM: 69%).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
Limited track record · 33 flights
Find Southwest 3191 fares Opens this date on Aviasales#3 · Southwest 1565
8:35 AM → 10:00 AM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-30.
88%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 0 min
- Arrived on time 100% of the time (8 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; 6 to 9 PM: 69%).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find Southwest 1565 fares Opens this date on Aviasales#4 · Southwest 1335
9:30 AM → 10:50 AM2h 20m nonstop
Local times, typical schedule. Last flown 2026-05-29.
87%
chance on time
- On time (history)
- 91%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 91% of the time (23 flights, Jun 2025 to May 2026).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- Short track record (23 flights), so its score leans on the airline's record at this hour.
Limited track record · 23 flights
Find Southwest 1335 fares Opens this date on Aviasales#5 · Southwest 1557
9:20 AM → 10:50 AM2h 30m nonstop
Local times, typical schedule. Last flown 2026-04-06.
87%
chance on time
- On time (history)
- 90%
- Cancelled
- 0.0%
- Avg arrival delay
- 14 min
- Arrived on time 90% of the time (20 flights, Jun 2025 to May 2026).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- Short track record (20 flights), so its score leans on the airline's record at this hour.
Limited track record · 20 flights
Find Southwest 1557 fares Opens this date on Aviasales#6 · Southwest 2496
9:45 AM → 11:05 AM2h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31.
86%
chance on time
- On time (history)
- 88%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 88% of the time (8 flights, Jun 2025 to May 2026).
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find Southwest 2496 fares Opens this date on Aviasales#7 · Southwest 1337
10:00 PM → 11:25 PM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31.
81%
chance on time
- On time (history)
- 87%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 87% of the time (46 flights, Jun 2025 to May 2026).
- Never cancelled in 46 scheduled flights.
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- Short track record (46 flights), so its score leans on the airline's record at this hour.
Limited track record · 46 flights
Find Southwest 1337 fares Opens this date on Aviasales#8 · Southwest 3835
4:25 PM → 5:50 PM2h 25m nonstop
Local times, typical schedule. Last flown 2026-04-06.
76%
chance on time
- On time (history)
- 70%
- Cancelled
- 0.0%
- Avg arrival delay
- 14 min
- Arrived on time 70% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- Departs inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
- Short track record (33 flights), so its score leans on the airline's record at this hour.
Limited track record · 33 flights
Find Southwest 3835 fares Opens this date on Aviasales#9 · Southwest 1788
9:40 PM → 11:05 PM2h 25m nonstop
Local times, typical schedule. Last flown 2026-04-06.
72%
chance on time
- On time (history)
- 67%
- Cancelled
- 0.0%
- Avg arrival delay
- 21 min
- Arrived on time 67% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- Departs outside BWI's trouble window (2 PM to 8 PM, when 81% of its 43 ground stops and delay programs started).
- 50% of its delay minutes came from the plane arriving late from an earlier flight.
Limited track record · 33 flights
Find Southwest 1788 fares Opens this date on Aviasales#10 · Southwest 987
6:20 PM → 7:45 PM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31.
71%
chance on time
- On time (history)
- 67%
- Cancelled
- 0.0%
- Avg arrival delay
- 16 min
- Arrived on time 67% of the time (54 flights, Jun 2025 to May 2026).
- Never cancelled in 55 scheduled flights.
- Leaves in this route's least on-time window (6 to 9 PM: 69% on time; Before 9 AM: 94%).
- Departs inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 54 flights
Find Southwest 987 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines82%
1,283 flights · 83% on time as flown · 1.2% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM94%
358 flights · avg delay 4 min
- 9 AM to noon93%
199 flights · avg delay 6 min
- Noon to 3 PM82%
139 flights · avg delay 11 min
- 3 to 6 PM84%
129 flights · avg delay 14 min
- 6 to 9 PM69%
259 flights · avg delay 19 min
- After 9 PM70%
199 flights · avg delay 23 min
Best day: Tuesday (81%). Worst: Saturday (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 aircraft53%
- Airline (crew, maintenance, boarding)31%
- Air traffic control and airport volume12%
- Severe weather3%
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
BWI to STL questions
- What time of day is best to fly BWI to STL?
- Before 9 AM: 94% of flights arrived on time, against 69% 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 BWI to STL?
- Southwest, with a season-adjusted 82% chance of operating and arriving on time over 1,283 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 BWI to STL?
- July (60% on time); the best was February (89%), 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 BWI
- STL to BWI (return)
- BWI to ATL 79%
- BWI to MCO 75%
- BWI to BOS 74%
- BWI to FLL 75%
- BWI to CLT 80%
- BWI to DEN 76%
- BWI to TPA 79%
- BWI to ORD 75%
- BWI to MIA 74%
- BWI to DTW 81%
- BWI to PVD 78%
- BWI to BNA 80%
Live status: FAA delays and ground stops