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.
GRR → MDW
Grand Rapids to Chicago: 928 nonstop flights a year
On time (12 months)
78%
Cancelled
0.4%
avg delay 12 min
Best time to leave
Before 9 AM
84% on time vs 62% 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 4375
12:30 PM → 12:30 PM1h 00m nonstop
Local times, typical schedule. Last flown 2026-05-31.
88%
chance on time
- On time (history)
- 96%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 96% of the time (46 flights, Jun 2025 to May 2026).
- Never cancelled in 46 scheduled flights.
- Lands inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- Short track record (46 flights), so its score leans on the airline's record at this hour.
Limited track record · 46 flights
Find Southwest 4375 fares Opens this date on Aviasales#2 · Southwest 2237
6:30 AM → 6:35 AM1h 00m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 3238; its record covers all of them.
82%
chance on time
- On time (history)
- 85%
- Cancelled
- 2.3%
- Avg arrival delay
- 6 min
- Arrived on time 85% of the time (85 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 84% on time; 6 to 9 PM: 62%).
Moderate track record · 85 flights
Find Southwest 2237 fares Opens this date on Aviasales#3 · Southwest 4400
12:40 PM → 12:45 PM1h 05m nonstop
Local times, typical schedule. Last flown 2026-04-06.
78%
chance on time
- On time (history)
- 75%
- Cancelled
- 0.0%
- Avg arrival delay
- 24 min
- Arrived on time 75% of the time (28 flights, Jun 2025 to May 2026).
- Lands inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- 57% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (28 flights), so its score leans on the airline's record at this hour.
Limited track record · 28 flights
Find Southwest 4400 fares Opens this date on Aviasales#4 · Southwest 3017
5:50 PM → 5:55 PM1h 05m nonstop
Local times, typical schedule. Last flown 2026-04-06.
73%
chance on time
- On time (history)
- 73%
- Cancelled
- 0.0%
- Avg arrival delay
- 14 min
- Arrived on time 73% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- 67% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (33 flights), so its score leans on the airline's record at this hour.
Limited track record · 33 flights
Find Southwest 3017 fares Opens this date on Aviasales#5 · Southwest 2194
5:40 PM → 5:45 PM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
71%
chance on time
- On time (history)
- 72%
- Cancelled
- 0.0%
- Avg arrival delay
- 15 min
- Arrived on time 72% of the time (54 flights, Jun 2025 to May 2026).
- Never cancelled in 54 scheduled flights.
- Short track record (54 flights), so its score leans on the airline's record at this hour.
Limited track record · 54 flights
Find Southwest 2194 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines77%
928 flights · 78% on time as flown · 0.4% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM84%
349 flights · avg delay 8 min
- Noon to 3 PM83%
196 flights · avg delay 11 min
- 3 to 6 PM76%
207 flights · avg delay 13 min
- 6 to 9 PM62%
160 flights · avg delay 21 min
Best day: Saturday (84%). Worst: Sunday (80%).
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