Today looks rough: weather pushes the average chance of arriving 15+ min late to 40%, against 24% on a calm day. Safest: DL 3692 at 19:40, 35%.

Safest bet today DL 3692 SEA 19:40 → BOI 22:18 · 35% chance 15+ min late · usually 87% on time Riskiest DL 3688 SEA 16:10 → BOI 18:46 · 46% chance 15+ min late · usually 86% on time

Weather 40% average chance a nonstop arrives 15+ min late; 24% 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. 11 flights that already left today are not shown.


DL 3692 Delta flown by SkyWest Flight history →	SEA 19:40	BOI 22:18	35%	11%	0.2%	87%worse than usual
DL 4090 Delta flown by SkyWest Flight history →	SEA 21:20	BOI 23:51	35%	10%	0.3%	85%worse than usual
AS 445 Alaska	SEA 21:31	BOI 00:01	44%	9%	0.2%	no record
DL 3688 Delta flown by SkyWest Flight history →	SEA 16:10	BOI 18:46	46%	15%	0.3%	86%worse than usual
AS 2034 Alaska flown by Horizon no forecast: 12-month record	SEA 19:59	BOI 22:24	14%	8%	0.0%	86%
AS 2109 Alaska flown by Horizon no forecast: 12-month record	SEA 17:40	BOI 20:07	18%	2%	0.7%	82%

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