Today looks rough: weather pushes the average chance of arriving 15+ min late to 55%, against 32% on a calm day. Safest: DL 3956 at 20:30, 39%.

Safest bet today DL 3956 SEA 20:30 → SJC 22:48 · 39% chance 15+ min late · usually 79% on time Riskiest WN 1585 SEA 18:50 → SJC 21:05 · 67% chance 15+ min late

Weather 55% average chance a nonstop arrives 15+ min late; 32% 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. 19 flights that already left today are not shown.


DL 3956 Delta flown by SkyWest Flight history →	SEA 20:30	SJC 22:48	39%	8%	0.3%	79%worse than usual
AS 403 Alaska	SEA 20:48	SJC 23:01	51%	10%	0.3%	no record
WN 3727 Southwest	SEA 21:10	SJC 23:26	63%	20%	0.1%	no record
WN 1585 Southwest	SEA 18:50	SJC 21:05	67%	18%	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