ATIS Alerts Smart Flight Search
Find the flight least likely to be delayed
BetaWe rank real flight numbers by how often they flew and arrived on time over the last 12 months, adjusted for your travel month and departure time, then check nearby airports and calmer connections. US airlines and airports.
MDW → PHL
Chicago to Philadelphia: 1,530 nonstop flights a year
On time (12 months)
75%
Cancelled
1.3%
avg delay 17 min
Best time to leave
Before 9 AM
90% on time vs 47% after 9 PM
Most reliable airline
Southwest
74% chance on time
Lowest nonstop fare seen in the next two months: $119 (Southwest 4363 on 2026-11-02). 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 3336
7:40 AM → 10:35 AM1h 55m nonstop
Local times, typical schedule. Last flown 2026-05-30.
91%
chance on time
- On time (history)
- 98%
- Cancelled
- 0.0%
- Avg arrival delay
- 2 min
- Arrived on time 98% of the time (47 flights, Jun 2025 to May 2026).
- Never cancelled in 47 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 90% on time; After 9 PM: 47%).
- Departs inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
Limited track record · 47 flights
Find Southwest 3336 fares Opens this date on Aviasales#2 · Southwest 2441
12:55 PM → 3:50 PM1h 55m nonstop
Local times, typical schedule. Last flown 2026-05-31.
79%
chance on time
- On time (history)
- 82%
- Cancelled
- 0.0%
- Avg arrival delay
- 7 min
- Arrived on time 82% of the time (55 flights, Jun 2025 to May 2026).
- Never cancelled in 55 scheduled flights.
- Departs inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- Lands inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 55 flights
Find Southwest 2441 fares Opens this date on Aviasales#3 · Southwest 3978
8:00 AM → 11:00 AM2h 00m nonstop
Local times, typical schedule. Last flown 2026-04-06.
77%
chance on time
- On time (history)
- 77%
- Cancelled
- 3.6%
- Avg arrival delay
- 16 min
- Arrived on time 77% of the time (26 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 90% on time; After 9 PM: 47%).
- Departs inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- 54% of its delay minutes came from the plane arriving late from an earlier flight.
Limited track record · 26 flights
Find Southwest 3978 fares Opens this date on Aviasales#4 · Southwest 1625
1:55 PM → 4:45 PM1h 50m nonstop
Local times, typical schedule. Last flown 2026-04-06.
70%
chance on time
- On time (history)
- 67%
- Cancelled
- 0.0%
- Avg arrival delay
- 26 min
- Arrived on time 67% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- Departs outside MDW's trouble window (7 AM to 1 PM, when 50% of its 30 ground stops and delay programs started).
- Lands inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 33 flights
Find Southwest 1625 fares Opens this date on Aviasales#5 · Southwest 1906
6:45 PM → 9:45 PM2h 00m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 745; its record covers all of them.
68%
chance on time
- On time (history)
- 67%
- Cancelled
- 1.3%
- Avg arrival delay
- 16 min
- Arrived on time 67% of the time (79 flights, Jun 2025 to May 2026).
- Departs outside MDW's trouble window (7 AM to 1 PM, when 50% of its 30 ground stops and delay programs started).
Moderate track record · 79 flights
Find Southwest 1906 fares Opens this date on Aviasales#6 · Southwest 3611
3:25 PM → 6:25 PM2h 00m nonstop
Local times, typical schedule. Last flown 2026-05-31.
56%
chance on time
- On time (history)
- 53%
- Cancelled
- 0.0%
- Avg arrival delay
- 23 min
- Arrived on time 53% of the time (55 flights, Jun 2025 to May 2026).
- Never cancelled in 55 scheduled flights.
- Departs outside MDW's trouble window (7 AM to 1 PM, when 50% of its 30 ground stops and delay programs started).
- Lands inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 55 flights
Find Southwest 3611 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines74%
1,445 flights · 74% on time as flown · 1.3% cancel
- Frontier Airlines73%
85 flights · 76% on time as flown · 1.7% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM90%
299 flights · avg delay 6 min
- 9 AM to noon86%
286 flights · avg delay 7 min
- Noon to 3 PM73%
388 flights · avg delay 16 min
- 3 to 6 PM58%
212 flights · avg delay 29 min
- 6 to 9 PM68%
273 flights · avg delay 22 min
- After 9 PM47%
72 flights · avg delay 45 min
Best day: Saturday (81%). Worst: Monday (71%).
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