Sunday, October 11 · typical odds for a Sunday (too early for a weather forecast) · issued Mon 8:00 PM ET · 6 nonstops

Sun, Oct 11: UA 2661 at 10:40 is the safest bet, 25% chance of being 15+ min late; evening flights run 29–39%.

Safest bet that day UA 2661 SFO 10:40 → ONT 12:12 · 25% chance 15+ min late · usually 78% on time Riskiest F9 1160 SFO 17:59 → ONT 19:38 · 39% chance 15+ min late

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 2661 United Flight history →	SFO 10:40	ONT 12:12	25%	11%	0.6%	78%
OO 5571 SkyWest	SFO 13:57	ONT 15:45	28%	16%	0.8%	no record
UA 2478 United	SFO 18:53	ONT 20:30	29%	13%	0.5%	no record
UA 552 United Flight history →	SFO 21:00	ONT 22:37	30%	13%	0.6%	83%worse than usual
OO 5467 SkyWest	SFO 16:13	ONT 17:50	32%	16%	0.8%	no record
F9 1160 Frontier	SFO 17:59	ONT 19:38	39%	17%	1.3%	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 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