Monday, October 5 · our forecast odds · issued Sun 6:00 PM ET · 4 nonstops

Tomorrow: WN 4809 at 07:10 is the safest bet, 5% chance of being 15+ min late; evening flights run 20%.

Safest bet that day WN 4809 SAT 07:10 → STL 09:15 · 5% chance 15+ min late · usually 90% on time Riskiest WN 3732 SAT 17:00 → STL 19:15 · 20% chance 15+ min late

Against a calm day 12% average chance a nonstop arrives 15+ min late; 11% 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 4809 Southwest Flight history →	SAT 07:10	STL 09:15	5%	2%	0.4%	90%
WN 1451 Southwest	SAT 07:40	STL 09:55	5%	2%	0.4%	no record
WN 3590 Southwest Flight history →	SAT 16:50	STL 19:00	20%	4%	0.5%	50%
WN 3732 Southwest	SAT 17:00	STL 19:15	20%	4%	0.5%	no record

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