Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 18 nonstops

Fri, Oct 9: WN 4331 at 07:05 is the safest bet, 9% chance of being 15+ min late; evening flights run 25–42%.

Safest bet that day WN 4331 DEN 07:05 → SAN 08:30 · 9% chance 15+ min late · usually 100% on time Riskiest WN 1703 DEN 18:55 → SAN 20:15 · 42% chance 15+ min late · usually 19% 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 4331 Southwest Flight history →	DEN 07:05	SAN 08:30	9%	1%	0.6%	100%
AS 1617 Alaska Flight history →	DEN 06:00	SAN 07:34	11%	2%	0.8%	94%
WN 1699 Southwest Flight history →	DEN 08:15	SAN 09:40	14%	2%	0.6%	86%
UA 2309 United Flight history →	DEN 07:43	SAN 09:05	14%	4%	0.6%	90%
UA 1940 United Flight history →	DEN 11:15	SAN 12:41	23%	8%	0.6%	82%
AS 1618 Alaska Flight history →	DEN 11:32	SAN 13:05	24%	6%	0.7%	80%
UA 1302 United Flight history →	DEN 13:30	SAN 14:55	24%	8%	0.6%	87%worse than usual
F9 2421 Frontier Flight history →	DEN 07:40	SAN 09:05	24%	7%	0.9%	84%
UA 1835 United Flight history →	DEN 21:00	SAN 22:25	25%	7%	0.6%	68%
UA 1281 United Flight history →	DEN 15:55	SAN 17:20	25%	9%	0.6%	85%worse than usual
WN 1700 Southwest Flight history →	DEN 10:40	SAN 12:05	28%	6%	0.6%	81%
UA 540 United Flight history →	DEN 19:20	SAN 20:46	28%	9%	0.6%	65%
F9 4989 Frontier Flight history →	DEN 22:29	SAN 23:51	29%	8%	1.1%	77%
AS 3020 Alaska flown by SkyWest Flight history →	DEN 19:59	SAN 21:40	29%	10%	1.0%	27%
WN 1704 Southwest Flight history →	DEN 21:50	SAN 23:20	31%	8%	0.6%	50%
WN 3503 Southwest Flight history →	DEN 12:55	SAN 14:15	32%	8%	0.6%	45%
WN 4160 Southwest Flight history →	DEN 16:55	SAN 18:20	37%	9%	0.6%	41%
WN 1703 Southwest Flight history →	DEN 18:55	SAN 20:15	42%	11%	0.6%	19%

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