Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 6 nonstops

Fri, Oct 9: DL 4104 at 11:40 is the safest bet, 16% chance of being 15+ min late; evening flights run 18–28%.

Safest bet that day DL 4104 SEA 11:40 → BZN 14:35 · 16% chance 15+ min late · usually 84% on time Riskiest AS 285 SEA 11:29 → BZN 14:09 · 28% chance 15+ min late · usually 71% on time

Every nonstop on Fri, Oct 9

12-month record →

Ranked by the chance of arriving 15+ minutes late (typical odds: the weather this date has had in past years), 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.


DL 4104 Delta flown by SkyWest Flight history →	SEA 11:40	BZN 14:35	16%	4%	0.5%	84%
DL 4039 Delta flown by SkyWest Flight history →	SEA 19:59	BZN 22:49	18%	5%	0.6%	84%
AS 3498 Alaska flown by SkyWest Flight history →	SEA 15:35	BZN 18:18	18%	4%	0.5%	71%
AS 458 Alaska Flight history →	SEA 20:40	BZN 23:19	28%	7%	0.7%	67%
AS 285 Alaska Flight history →	SEA 11:29	BZN 14:09	28%	4%	0.6%	71%
AS 2141 Alaska flown by Horizon no forecast: 12-month record	SEA 07:06	BZN 09:46	5%	1%	1.1%	95%

How these are worked out. Each flight’s odds are our forecast for that day (typical odds until the weather forecast covers it); 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 Fri, Oct 9 (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