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 4048 at 05:50 is the safest bet, 4% chance of being 15+ min late; the others run 11–26%.

Safest bet that day WN 4048 TPA 05:50 → STL 07:10 · 4% chance 15+ min late · usually 98% on time Riskiest WN 4964 TPA 21:10 → STL 22:40 · 26% chance 15+ min late · usually 65% 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 4048 Southwest Flight history →	TPA 05:50	STL 07:10	4%	1%	13.1%	98%
WN 4049 Southwest Flight history →	TPA 10:15	STL 11:40	11%	3%	17.1%	81%
WN 4964 Southwest Flight history →	TPA 21:10	STL 22:40	26%	9%	11.6%	65%

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