Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 3 nonstops

Fri, Oct 9: WN 3609 at 08:45 is the safest bet, 5% chance of being 15+ min late; the others run 13–19%.

Safest bet that day WN 3609 SDF 08:45 → MDW 09:00 · 5% chance 15+ min late · usually 97% on time Riskiest WN 3329 SDF 20:05 → MDW 20:20 · 19% chance 15+ min late · usually 92% on time

Every nonstop on Fri, Oct 9

12-month record →

Ranked by the chance of arriving 15+ minutes late (typical odds: the weather this date has had in past years), 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 3609 Southwest Flight history →	SDF 08:45	MDW 09:00	5%	1%	0.6%	97%
WN 3610 Southwest Flight history →	SDF 15:35	MDW 15:50	13%	3%	0.6%	75%
WN 3329 Southwest Flight history →	SDF 20:05	MDW 20:20	19%	4%	0.6%	92%worse than usual

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 Fri, Oct 9 (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