Today: WN 429 at 07:35 is the safest bet, 9% chance of being 15+ min late; evening flights run 22–24%.

Safest bet today WN 429 AUS 07:35 → STL 09:48 · 9% chance 15+ min late Riskiest WN 4684 AUS 17:10 → STL 19:15 · 24% chance 15+ min late · usually 35% on time

Against a calm day 17% average chance a nonstop arrives 15+ min late; 15% 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 429 Southwest	AUS 07:35	STL 09:48	9%	2%	0.1%	no record
WN 408 Southwest Flight history →	AUS 07:15	STL 09:15	9%	2%	0.1%	90%
WN 409 Southwest Flight history →	AUS 11:30	STL 13:35	17%	3%	0.1%	73%
WN 239 Southwest	AUS 13:40	STL 15:53	18%	4%	0.4%	no record
WN 4628 Southwest	AUS 17:01	STL 19:15	22%	5%	0.4%	no record
WN 4684 Southwest Flight history →	AUS 17:10	STL 19:15	24%	6%	0.4%	35%

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