Today looks rough: weather pushes the average chance of arriving 15+ min late to 59%, against 34% on a calm day. Safest: AS 403 at 20:34, 50%.

Safest bet today AS 403 SMF 20:34 → SEA 22:39 · 50% chance 15+ min late · usually 80% on time Riskiest AS 646 SMF 19:55 → SEA 21:17 · 75% chance 15+ min late

Weather 59% average chance a nonstop arrives 15+ min late; 34% 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. 18 flights that already left today are not shown.


AS 403 Alaska Flight history →	SMF 20:34	SEA 22:39	50%	14%	0.6%	80%worse than usual
DL 4043 Delta flown by SkyWest Flight history →	SMF 19:41	SEA 21:57	54%	14%	0.4%	81%worse than usual
WN 3974 Southwest	SMF 22:05	SEA 00:02	54%	22%	0.3%	no record
WN 693 Southwest	SMF 22:00	SEA 23:55	60%	30%	0.2%	no record
AS 646 Alaska	SMF 19:55	SEA 21:17	75%	19%	0.6%	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