Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 7 nonstops

Fri, Oct 9: WN 4179 at 09:05 is the safest bet, 10% chance of being 15+ min late; evening flights run 34–41%.

Safest bet that day WN 4179 LAS 09:05 → ONT 10:10 · 10% chance 15+ min late · usually 82% on time Riskiest WN 208 LAS 19:10 → ONT 20:10 · 41% chance 15+ min late · usually 56% 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.


WN 4179 Southwest Flight history →	LAS 09:05	ONT 10:10	10%	2%	0.6%	82%
F9 1283 Frontier Flight history →	LAS 07:00	ONT 08:03	17%	6%	0.9%	86%
WN 2298 Southwest Flight history →	LAS 11:45	ONT 12:45	24%	5%	0.6%	82%
WN 2135 Southwest Flight history →	LAS 22:25	ONT 23:35	34%	12%	0.6%	23%
WN 3845 Southwest Flight history →	LAS 14:20	ONT 15:25	35%	9%	0.7%	52%
F9 1357 Frontier Flight history →	LAS 14:45	ONT 15:54	35%	15%	1.3%	82%worse than usual
WN 208 Southwest Flight history →	LAS 19:10	ONT 20:10	41%	15%	0.9%	56%

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