Today looks rough: weather pushes the average chance of arriving 15+ min late to 55%, against 31% on a calm day. Safest: DL 4100 at 20:59, 38%.

Safest bet today DL 4100 SJC 20:59 → SEA 23:23 · 38% chance 15+ min late · usually 88% on time Riskiest WN 3703 SJC 20:20 → SEA 22:28 · 75% chance 15+ min late

Weather 55% average chance a nonstop arrives 15+ min late; 31% 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. 16 flights that already left today are not shown.


DL 4100 Delta flown by SkyWest Flight history →	SJC 20:59	SEA 23:23	38%	9%	0.6%	88%worse than usual
AS 1436 Alaska Flight history →	SJC 21:38	SEA 23:47	48%	14%	1.3%	69%worse than usual
AS 745 Alaska Flight history →	SJC 20:44	SEA 22:50	49%	14%	1.3%	83%worse than usual
AS 481 Alaska Flight history →	SJC 18:45	SEA 21:00	55%	14%	1.3%	53%
WN 3705 Southwest Flight history →	SJC 21:35	SEA 23:50	64%	25%	0.3%	64%worse than usual
WN 3703 Southwest	SJC 20:20	SEA 22:28	75%	24%	0.3%	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