Today looks rough: weather pushes the average chance of arriving 15+ min late to 58%, against 46% on a calm day. Safest: DL 3923 at 20:44, 56%.

Safest bet today DL 3923 PDX 20:44 → SEA 21:56 · 56% chance 15+ min late · usually 79% on time Riskiest OO 4096 PDX 20:47 → SEA 21:50 · 60% chance 15+ min late

Weather 58% average chance a nonstop arrives 15+ min late; 46% 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. Dimmed: airlines we don’t forecast yet, shown with their 12-month record if they usually fly that weekday. 27 flights that already left today are not shown.


DL 3923 Delta flown by SkyWest Flight history →	PDX 20:44	SEA 21:56	56%	14%	0.6%	79%worse than usual
OO 4096 SkyWest	PDX 20:47	SEA 21:50	60%	14%	0.6%	no record
AS 2421 Alaska flown by Horizon no forecast: 12-month record	PDX 21:30	SEA 22:27	10%	6%	0.0%	90%

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