Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sat 8:00 PM ET · 23 nonstops

Fri, Oct 9: WN 3615 at 05:15 is the safest bet, 5% chance of being 15+ min late; evening flights run 17–37%.

Safest bet that day WN 3615 SEA 05:15 → DEN 08:50 · 5% chance 15+ min late · usually 95% on time Riskiest WN 3617 SEA 14:35 → DEN 18:20 · 38% chance 15+ min late · usually 14% 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 3615 Southwest Flight history →	SEA 05:15	DEN 08:50	5%	1%	0.5%	95%
UA 2601 United Flight history →	SEA 05:00	DEN 08:43	5%	2%	0.6%	96%
WN 3397 Southwest Flight history →	SEA 07:50	DEN 11:25	13%	3%	0.5%	93%
DL 1358 Delta Flight history →	SEA 08:10	DEN 12:02	14%	4%	0.7%	85%
UA 1505 United Flight history →	SEA 08:56	DEN 12:45	14%	3%	0.6%	92%
UA 1351 United Flight history →	SEA 12:50	DEN 16:42	16%	4%	0.6%	89%
UA 757 United Flight history →	SEA 11:02	DEN 14:51	17%	4%	0.6%	88%
UA 1218 United Flight history →	SEA 20:05	DEN 23:49	17%	5%	0.6%	84%
AS 375 Alaska Flight history →	SEA 08:04	DEN 11:56	19%	3%	0.6%	88%
UA 325 United Flight history →	SEA 15:40	DEN 19:29	21%	5%	0.6%	86%
UA 333 United Flight history →	SEA 14:33	DEN 18:22	22%	6%	0.6%	66%
DL 2851 Delta Flight history →	SEA 19:59	DEN 23:44	22%	8%	0.7%	78%
F9 3406 Frontier Flight history →	SEA 12:35	DEN 16:40	26%	7%	0.9%	78%
DL 2543 Delta Flight history →	SEA 13:50	DEN 17:43	27%	8%	0.7%	39%
AS 642 Alaska Flight history →	SEA 20:11	DEN 23:59	28%	6%	0.6%	81%
WN 3616 Southwest Flight history →	SEA 12:20	DEN 16:10	28%	6%	0.5%	44%
AS 310 Alaska Flight history →	SEA 19:00	DEN 22:45	30%	7%	0.6%	65%
AS 535 Alaska Flight history →	SEA 11:44	DEN 15:38	31%	5%	0.6%	78%
F9 1176 Frontier Flight history →	SEA 19:06	DEN 22:58	32%	10%	1.0%	78%
AS 602 Alaska Flight history →	SEA 16:26	DEN 20:10	32%	7%	0.6%	76%
AS 242 Alaska Flight history →	SEA 13:33	DEN 17:20	36%	7%	0.6%	70%
WN 4845 Southwest Flight history →	SEA 19:30	DEN 23:10	37%	10%	0.5%	40%
WN 3617 Southwest Flight history →	SEA 14:35	DEN 18:20	38%	9%	0.5%	14%

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