Today looks rough: weather pushes the average chance of arriving 15+ min late to 49%, against 23% on a calm day. Safest: UA 1035 at 18:37, 35%.

Safest bet today UA 1035 SJC 18:37 → DEN 22:16 · 35% chance 15+ min late · usually 80% on time Riskiest WN 3800 SJC 17:25 → DEN 20:50 · 58% chance 15+ min late

Weather 49% 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. 10 flights that already left today are not shown.


UA 1035 United Flight history →	SJC 18:37	DEN 22:16	35%	11%	0.2%	80%worse than usual
WN 1225 Southwest	SJC 20:40	DEN 00:10	46%	14%	0.1%	no record
WN 3426 Southwest	SJC 17:41	DEN 21:13	56%	18%	0.1%	no record
WN 3800 Southwest	SJC 17:25	DEN 20:50	58%	15%	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