Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 6 nonstops

Fri, Oct 9: WN 1008 at 05:40 is the safest bet, 4% chance of being 15+ min late; evening flights run 25–26%.

Safest bet that day WN 1008 STL 05:40 → MDW 06:45 · 4% chance 15+ min late · usually 89% on time Riskiest WN 596 STL 18:30 → MDW 19:35 · 26% chance 15+ min late · usually 52% 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 1008 Southwest Flight history →	STL 05:40	MDW 06:45	4%	1%	0.6%	89%
WN 2570 Southwest Flight history →	STL 08:55	MDW 10:00	8%	1%	0.6%	88%
WN 3344 Southwest Flight history →	STL 12:40	MDW 13:45	14%	3%	0.6%	60%
WN 556 Southwest Flight history →	STL 15:35	MDW 16:40	20%	5%	0.6%	61%
WN 3957 Southwest Flight history →	STL 21:55	MDW 23:05	25%	7%	0.6%	67%
WN 596 Southwest Flight history →	STL 18:30	MDW 19:35	26%	6%	0.6%	52%

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