Today looks rough: weather pushes the average chance of arriving 15+ min late to 47%, against 23% on a calm day. Safest: F9 4567 at 20:08, 46%.

Safest bet today F9 4567 STL 20:08 → DEN 21:44 · 46% chance 15+ min late · usually 76% on time Riskiest WN 1713 STL 19:01 → DEN 20:25 · 48% chance 15+ min late

Weather 47% average chance a nonstop arrives 15+ min late; 23% 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. 17 flights that already left today are not shown.


F9 4567 Frontier Flight history →	STL 20:08	DEN 21:44	46%	20%	0.7%	76%worse than usual
WN 2419 Southwest	STL 21:45	DEN 23:08	46%	13%	0.2%	no record
WN 4243 Southwest	STL 21:45	DEN 23:10	47%	14%	0.2%	no record
WN 1713 Southwest	STL 19:01	DEN 20:25	48%	12%	0.1%	no record

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