Today: WN 3962 at 11:36 is the safest bet, 31% chance of being 15+ min late; evening flights run 45–48%.

Safest bet today WN 3962 DAL 11:36 → STL 13:32 · 31% chance 15+ min late Riskiest WN 4151 DAL 22:55 → STL 00:45 · 48% chance 15+ min late

Against a calm day 43% average chance a nonstop arrives 15+ min late; 38% for the same flights on a calm-weather day

Every nonstop today

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. 3 flights that already left today are not shown.


WN 3962 Southwest	DAL 11:36	STL 13:32	31%	7%	0.6%	no record
WN 1346 Southwest	DAL 13:00	STL 14:45	36%	10%	0.6%	no record
WN 1809 Southwest	DAL 17:25	STL 19:21	45%	7%	0.6%	no record
WN 1469 Southwest	DAL 14:16	STL 16:07	45%	9%	0.6%	no record
WN 1418 Southwest	DAL 21:30	STL 23:21	46%	9%	0.5%	no record
WN 3456 Southwest	DAL 17:25	STL 19:10	46%	8%	0.6%	no record
WN 379 Southwest	DAL 20:00	STL 21:45	47%	11%	0.5%	no record
WN 4151 Southwest	DAL 22:55	STL 00:45	48%	10%	0.7%	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 Sun, Oct 4 (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