Today: WN 2931 at 07:15 is the safest bet, 7% chance of being 15+ min late; evening flights run 28–30%.

Safest bet today WN 2931 MIA 07:15 → STL 09:05 · 7% chance 15+ min late · usually 95% on time Riskiest AA 1594 MIA 20:54 → STL 22:54 · 30% chance 15+ min late · usually 61% on time

Against a calm day 19% average chance a nonstop arrives 15+ min late; 22% 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 2931 Southwest Flight history →	MIA 07:15	STL 09:05	7%	2%	0.1%	95%
AA 3954 American flown by Envoy Flight history →	MIA 08:23	STL 10:24	8%	2%	0.2%	94%
AA 477 American	MIA 15:41	STL 17:39	21%	7%	0.2%	no record
WN 3040 Southwest	MIA 19:10	STL 21:03	28%	7%	0.5%	no record
AA 1594 American Flight history →	MIA 20:54	STL 22:54	30%	7%	0.8%	61%

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