Today looks rough: weather pushes the average chance of arriving 15+ min late to 56%, against 39% on a calm day. Safest: UA 1422 at 17:34, 40%.

Safest bet today UA 1422 DEN 17:34 → STL 20:43 · 40% chance 15+ min late · usually 72% on time Riskiest WN 3317 DEN 20:45 → STL 23:55 · 67% chance 15+ min late · usually 41% on time

Weather 56% average chance a nonstop arrives 15+ min late; 39% 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. 13 flights that already left today are not shown.


UA 1422 United Flight history →	DEN 17:34	STL 20:43	40%	12%	0.1%	72%worse than usual
UA 214 United Flight history →	DEN 20:45	STL 23:57	48%	12%	0.1%	58%
OO 4733 SkyWest	DEN 20:30	STL 23:45	51%	13%	0.2%	no record
WN 1718 Southwest	DEN 17:50	STL 21:05	58%	14%	0.1%	no record
WN 1758 Southwest	DEN 19:00	STL 22:10	64%	14%	0.1%	no record
WN 1305 Southwest	DEN 19:10	STL 22:18	65%	14%	0.1%	no record
WN 3317 Southwest Flight history →	DEN 20:45	STL 23:55	67%	16%	0.1%	41%

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