Monday, October 5 · our forecast odds · issued Sun 5:00 PM ET · 3 nonstops

Tomorrow: WN 4377 at 06:00 is the safest bet, 8% chance of being 15+ min late; the others run 12–18%.

Safest bet that day WN 4377 SJC 06:00 → MDW 12:09 · 8% chance 15+ min late Riskiest WN 4357 SJC 10:05 → MDW 16:10 · 18% chance 15+ min late · usually 65% on time

Against a calm day 13% average chance a nonstop arrives 15+ min late; 10% for the same flights on a calm-weather day

Every nonstop on Mon, Oct 5

12-month record →

Ranked by the chance of arriving 15+ minutes late, with each flight’s on-time record over Aug 2025 – Jul 2026 beside it. Times are local. Pick a flight for its forecast. Click a column to sort.


WN 4377 Southwest	SJC 06:00	MDW 12:09	8%	1%	0.6%	no record
WN 3886 Southwest Flight history →	SJC 22:55	MDW 05:00	12%	3%	0.5%	94%
WN 4357 Southwest Flight history →	SJC 10:05	MDW 16:10	18%	2%	0.6%	65%

How these are worked out. Each flight’s odds are our forecast for that day; 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 Mon, Oct 5 (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