Sunday, October 11 · typical odds for a Sunday (too early for a weather forecast) · issued Mon 12:00 AM ET · 5 nonstops

Sun, Oct 11: UA 4678 at 06:30 is the safest bet, 5% chance of being 15+ min late; the others run 22–26%.

Safest bet that day UA 4678 BOI 06:30 → SFO 07:30 · 5% chance 15+ min late · usually 90% on time Riskiest UA 4639 BOI 08:15 → SFO 09:15 · 26% chance 15+ min late · usually 48% on time

Every nonstop on Sun, Oct 11

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%	3%	0.6%	90%
UA 4661 United flown by SkyWest Flight history →	BOI 14:00	SFO 14:58	22%	12%	0.6%	48%
UA 743 United	BOI 18:54	SFO 19:59	23%	12%	0.8%	no record
AS 3025 Alaska flown by SkyWest Flight history →	BOI 08:55	SFO 09:55	26%	13%	0.6%	60%
UA 4639 United flown by SkyWest Flight history →	BOI 08:15	SFO 09:15	26%	13%	0.6%	48%

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 Sun, Oct 11 (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