Today: WN 2519 at 05:05 is the safest bet, 3% chance of being 15+ min late; evening flights run 16–25%.

Safest bet today WN 2519 STL 05:05 → HOU 07:17 · 3% chance 15+ min late Riskiest WN 4617 STL 21:45 → HOU 23:50 · 25% chance 15+ min late · usually 52% on time

Against a calm day 14% average chance a nonstop arrives 15+ min late; 12% 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.


WN 2519 Southwest	STL 05:05	HOU 07:17	3%	1%	0.2%	no record
WN 3919 Southwest Flight history →	STL 05:00	HOU 07:05	4%	1%	0.2%	91%
WN 3928 Southwest Flight history →	STL 07:15	HOU 09:20	5%	2%	0.4%	88%
WN 4074 Southwest	STL 08:12	HOU 10:24	9%	2%	0.4%	no record
WN 3248 Southwest	STL 14:30	HOU 16:43	15%	3%	0.5%	no record
WN 4335 Southwest	STL 18:25	HOU 20:37	16%	4%	0.6%	no record
WN 4752 Southwest Flight history →	STL 13:50	HOU 15:55	18%	3%	0.5%	50%
WN 3004 Southwest	STL 22:25	HOU 00:35	18%	4%	0.6%	no record
WN 5065 Southwest Flight history →	STL 17:40	HOU 19:45	19%	4%	0.5%	73%
WN 3136 Southwest Flight history →	STL 18:50	HOU 20:55	19%	4%	0.5%	62%
WN 4617 Southwest Flight history →	STL 21:45	HOU 23:50	25%	4%	0.5%	52%

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