Today: WN 2129 at 09:00 is the safest bet, 10% chance of being 15+ min late; evening flights run 27–31%.

Safest bet today WN 2129 HOU 09:00 → STL 11:06 · 10% chance 15+ min late Riskiest WN 4724 HOU 17:10 → STL 19:10 · 31% chance 15+ min late · usually 73% on time

Against a calm day 20% average chance a nonstop arrives 15+ min late; 17% 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. 2 flights that already left today are not shown.


WN 2129 Southwest	HOU 09:00	STL 11:06	10%	2%	0.2%	no record
WN 2084 Southwest Flight history →	HOU 10:40	STL 12:45	12%	2%	0.2%	76%
WN 4642 Southwest Flight history →	HOU 13:20	STL 15:20	15%	3%	0.2%	76%
WN 4650 Southwest	HOU 12:55	STL 15:01	16%	3%	0.2%	no record
WN 5064 Southwest Flight history →	HOU 15:00	STL 17:00	22%	4%	0.2%	73%
WN 2870 Southwest	HOU 20:25	STL 22:32	27%	6%	0.6%	no record
WN 4790 Southwest	HOU 17:05	STL 19:12	27%	4%	0.2%	no record
WN 4724 Southwest Flight history →	HOU 17:10	STL 19:10	31%	4%	0.2%	73%

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