Saturday, October 10 · typical odds for a Saturday (too early for a weather forecast) · issued Mon 4:00 PM ET · 4 nonstops

Sat, Oct 10: UA 4639 at 08:20 is the safest bet, 23% chance of being 15+ min late; the others run 24–33%.

Safest bet that day UA 4639 BOI 08:20 → SFO 09:31 · 23% chance 15+ min late · usually 48% on time Riskiest UA 743 BOI 20:36 → SFO 21:25 · 33% chance 15+ min late

Every nonstop on Sat, Oct 10

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.


UA 4639 United flown by SkyWest Flight history →	BOI 08:20	SFO 09:31	23%	12%	0.6%	48%
UA 4661 United flown by SkyWest Flight history →	BOI 14:39	SFO 15:47	24%	13%	0.6%	48%
AS 3025 Alaska flown by SkyWest Flight history →	BOI 09:07	SFO 10:07	27%	13%	0.6%	60%
UA 743 United	BOI 20:36	SFO 21:25	33%	12%	0.7%	no record

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 Sat, Oct 10 (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