Today looks rough: weather pushes the average chance of arriving 15+ min late to 48%, against 28% on a calm day. Safest: WN 3187 at 18:01, 44%.

Safest bet today WN 3187 STL 18:01 → HOU 20:14 · 44% chance 15+ min late Riskiest WN 4617 STL 21:50 → HOU 23:55 · 52% chance 15+ min late · usually 52% on time

Weather 48% average chance a nonstop arrives 15+ min late; 28% 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. 6 flights that already left today are not shown.


WN 3187 Southwest	STL 18:01	HOU 20:14	44%	14%	0.5%	no record
WN 2312 Southwest	STL 18:35	HOU 20:40	46%	14%	0.5%	no record
WN 140 Southwest	STL 21:46	HOU 23:59	50%	11%	0.4%	no record
WN 4617 Southwest Flight history →	STL 21:50	HOU 23:55	52%	12%	0.4%	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 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