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.
SJC → MDW
San Jose to Chicago: 550 nonstop flights a year
On time (12 months)
83%
Cancelled
0.4%
avg delay 8 min
Best time to leave
After 9 PM
94% on time vs 70% noon to 3 PM
Most reliable airline
Southwest
84% chance on time
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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 4252
10:55 PM → 5:00 AM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 4447; its record covers all of them.
93%
chance on time
- On time (history)
- 94%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 94% of the time (87 flights, Jun 2025 to May 2026).
- Never cancelled in 87 scheduled flights.
- Leaves in this route's most on-time window (After 9 PM: 94% on time; Noon to 3 PM: 70%).
Moderate track record · 87 flights
Find Southwest 4252 fares Opens this date on Aviasales#2 · Southwest 3720
11:40 AM → 5:45 PM4h 05m nonstop
Local times, typical schedule. Last flown 2026-04-06.
77%
chance on time
- On time (history)
- 78%
- Cancelled
- 0.0%
- Avg arrival delay
- 9 min
- Arrived on time 78% of the time (23 flights, Jun 2025 to May 2026).
- Short track record (23 flights), so its score leans on the airline's record at this hour.
Limited track record · 23 flights
Find Southwest 3720 fares Opens this date on Aviasales#3 · Southwest 1877
11:30 AM → 5:35 PM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-29.
65%
chance on time
- On time (history)
- 47%
- Cancelled
- 0.0%
- Avg arrival delay
- 20 min
- Arrived on time 47% of the time (38 flights, Jun 2025 to May 2026).
- Never cancelled in 39 scheduled flights.
- Short track record (38 flights), so its score leans on the airline's record at this hour.
Limited track record · 38 flights
Find Southwest 1877 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines84%
550 flights · 83% on time as flown · 0.4% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM92%
215 flights · avg delay 4 min
- 9 AM to noon74%
170 flights · avg delay 11 min
- Noon to 3 PM70%
51 flights · avg delay 13 min
- After 9 PM94%
88 flights · avg delay 3 min
Best day: Saturday (92%). Worst: Monday (81%).
Smarter routing
Nearby airports that run more on time
SJC → ORD 91% chance on time
Norman Y. Mineta San Jose International Airport to Chicago O'Hare International Airport · 301 flights a year · 15 mi from your airports · yours: 83%
OAK → MDW 88% chance on time
Oakland San Francisco Bay Airport to Chicago Midway International Airport · 459 flights a year · 29 mi from your airports · yours: 83%
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