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

Fri, Oct 9: WN 4873 at 07:20 is the safest bet, 9% chance of being 15+ min late; evening flights run 21–31%.

Safest bet that day WN 4873 SAN 07:20 → BOI 10:30 · 9% chance 15+ min late · usually 76% on time Riskiest WN 644 SAN 21:05 → BOI 00:25 · 31% chance 15+ min late · usually 73% 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.


WN 4873 Southwest Flight history →	SAN 07:20	BOI 10:30	9%	2%	0.6%	76%
AS 3331 Alaska flown by SkyWest Flight history →	SAN 17:06	BOI 20:25	21%	7%	0.6%	79%
WN 644 Southwest Flight history →	SAN 21:05	BOI 00:25	31%	7%	0.6%	73%
AS 2341 Alaska flown by Horizon no forecast: 12-month record	SAN 10:30	BOI 13:46	25%	4%	0.0%	75%

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