Today: WN 3386 at 06:45 is the safest bet, 3% chance of being 15+ min late; evening flights run 15–19%.

Safest bet today WN 3386 PIT 06:45 → STL 07:30 · 3% chance 15+ min late · usually 95% on time Riskiest WN 3387 PIT 20:15 → STL 21:00 · 19% chance 15+ min late · usually 56% on time

Against a calm day 10% average chance a nonstop arrives 15+ min late; 11% 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 3386 Southwest Flight history →	PIT 06:45	STL 07:30	3%	1%	0.1%	95%
WN 3550 Southwest	PIT 06:50	STL 07:46	3%	1%	0.1%	no record
WN 3453 Southwest	PIT 20:20	STL 21:16	15%	5%	0.4%	no record
WN 3387 Southwest Flight history →	PIT 20:15	STL 21:00	19%	5%	0.4%	56%

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