Monday, October 12 · typical odds for a Monday (too early for a weather forecast) · issued Tue 12:00 AM ET · 5 nonstops

Mon, Oct 12: UA 4678 at 06:30 is the safest bet, 5% chance of being 15+ min late; the others run 18–25%.

Safest bet that day UA 4678 BOI 06:30 → SFO 07:30 · 5% chance 15+ min late · usually 90% on time Riskiest AS 3025 BOI 08:53 → SFO 09:54 · 25% chance 15+ min late · usually 60% on time

Every nonstop on Mon, Oct 12

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 4678 United flown by SkyWest Flight history →	BOI 06:30	SFO 07:30	5%	2%	0.6%	90%
UA 4661 United flown by SkyWest Flight history →	BOI 14:55	SFO 16:23	18%	11%	0.6%	48%
UA 4639 United flown by SkyWest Flight history →	BOI 08:24	SFO 09:36	23%	10%	0.6%	48%
UA 743 United	BOI 18:47	SFO 19:37	23%	9%	0.8%	no record
AS 3025 Alaska flown by SkyWest Flight history →	BOI 08:53	SFO 09:54	25%	11%	0.6%	60%

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 Mon, Oct 12 (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