Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sat 8:00 PM ET · 4 nonstops

Fri, Oct 9 looks like a normal day here: all 4 nonstops are 24–32% likely to arrive 15+ min late.

Safest bet that day UA 2661 SFO 10:40 → ONT 12:12 · 24% chance 15+ min late · usually 78% on time Riskiest UA 5613 SFO 16:17 → ONT 17:54 · 32% chance 15+ min late · usually 67% 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.


UA 2661 United Flight history →	SFO 10:40	ONT 12:12	24%	8%	0.6%	78%
UA 552 United Flight history →	SFO 21:00	ONT 22:37	25%	9%	0.6%	83%
F9 2678 Frontier Flight history →	SFO 09:33	ONT 11:07	27%	9%	1.7%	58%
UA 5613 United flown by SkyWest Flight history →	SFO 16:17	ONT 17:54	32%	15%	1.0%	67%

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