Sunday, October 11 · typical odds for a Sunday (too early for a weather forecast) · issued Mon 12:00 AM ET · connections flying that day

Sun, Oct 11: WN 3657 at 10:05 is the safest bet, 25% chance of being 15+ min late; the others run 44%.

Nonstops that day

All 2 nonstops →


WN 3657 Southwest	MDW 10:05	SEA 12:35	25%	4%	0.7%	no record
WN 4366 Southwest	MDW 22:20	SEA 00:45	44%	10%	1.2%	no record

Best connections that day, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Seattle on time, from each leg’s forecast for the day. Total trip = scheduled departure to arrival (Seattle is 2 h behind Chicago). Layovers up to 4 hours. Pick a connection for its 12-month details.


Delta Details →	MDW 06:00 → ATL 08:57DL 1285	3h 36m Atlanta	ATL 12:33 → SEA 14:50DL 629	10h 50m	98%	80%
Delta Details →	MDW 09:54 → MSP 11:35DL 5469 · flown by Endeavor	3h 40m Minneapolis	MSP 15:15 → SEA 17:00DL 877	9h 06m	98%	76%
Delta Details →	MDW 11:05 → ATL 14:01DL 1063	2h 44m Atlanta	ATL 16:45 → SEA 19:05DL 472	10h 00m	97%	70%
Delta Details →	MDW 09:17 → DTW 11:35DL 4674 · flown by Endeavor	54m Detroit	DTW 12:29 → SEA 14:29DL 728	7h 12m	83%	67%
Delta Details →	MDW 13:49 → MSP 15:33DL 4820 · flown by Endeavor	3h 22m Minneapolis	MSP 18:55 → SEA 20:48DL 881	8h 59m	94%	67%
Delta Details →	MDW 12:41 → ATL 15:43DL 2417	2h 07m Atlanta	ATL 17:50 → SEA 20:11DL 714	9h 30m	96%	61%
Delta Details →	MDW 13:26 → DTW 15:44DL 4688 · flown by Endeavor	1h 02m Detroit	DTW 16:46 → SEA 18:42DL 944	7h 16m	81%	60%
Delta Details →	MDW 17:10 → ATL 20:22DL 1728	1h 13m Atlanta	ATL 21:35 → SEA 23:59DL 903	8h 49m	80%	53%
Tight connection: often missed
Delta Details →	MDW 19:06 → MSP 20:51DL 4713 · flown by Endeavor	1h 17m Minneapolis	MSP 22:08 → SEA 23:58DL 505	6h 52m	70%	55%

How these are worked out. Each flight’s odds are our forecast for that day (typical odds until the weather forecast covers it); flights of airlines we don’t forecast yet use their 12-month record and are marked. Makes the connection: the first flight’s 12-month lateness curve, scaled so its chance of arriving 15+ min late matches the day’s forecast, at the layover minus the 45-minute minimum (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled × second flight within 15 minutes, each from the day’s forecast.

About this data: forecast odds from our model for Sun, Oct 11 (newest published update); 12-month records from US DOT on-time data, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. JSON