Thursday, October 8 · typical odds for a Thursday (too early for a weather forecast) · issued Sun 12:00 PM ET · 4 nonstops

Thu, Oct 8: WN 3555 at 07:51 is the safest bet, 4% chance of being 15+ min late; the others run 6–14%.

Safest bet that day WN 3555 MDW 07:51 → STL 09:09 · 4% chance 15+ min late Riskiest WN 4699 MDW 17:51 → STL 19:10 · 14% chance 15+ min late

Every nonstop on Thu, Oct 8

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 3555 Southwest	MDW 07:51	STL 09:09	4%	1%	0.6%	no record
WN 806 Southwest	MDW 10:59	STL 12:18	6%	1%	0.6%	no record
WN 884 Southwest	MDW 14:46	STL 16:05	11%	3%	0.6%	no record
WN 4699 Southwest	MDW 17:51	STL 19:10	14%	4%	0.6%	no record

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 Thu, Oct 8 (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