Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Mon 12:00 PM ET · 15 nonstops

Fri, Oct 9: WN 3629 at 05:00 is the safest bet, 4% chance of being 15+ min late; evening flights run 16–37%.

Safest bet that day WN 3629 SEA 05:00 → SMF 06:50 · 4% chance 15+ min late · usually 98% on time Riskiest WN 3566 SEA 18:05 → SMF 20:05 · 37% chance 15+ min late · usually 61% 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 3629 Southwest Flight history →	SEA 05:00	SMF 06:50	4%	1%	0.5%	98%
WN 3630 Southwest Flight history →	SEA 07:35	SMF 09:35	8%	3%	0.5%	91%
DL 3881 Delta flown by SkyWest Flight history →	SEA 08:47	SMF 10:50	13%	3%	0.5%	92%
DL 4125 Delta flown by SkyWest Flight history →	SEA 10:10	SMF 12:17	14%	4%	0.5%	91%
AS 682 Alaska Flight history →	SEA 07:28	SMF 09:26	14%	3%	0.6%	94%
DL 4153 Delta flown by SkyWest Flight history →	SEA 14:40	SMF 16:39	15%	5%	0.5%	88%
DL 4131 Delta flown by SkyWest Flight history →	SEA 20:25	SMF 22:31	16%	5%	0.6%	91%
DL 4043 Delta flown by SkyWest Flight history →	SEA 17:00	SMF 18:57	21%	5%	0.6%	89%
AS 1380 Alaska Flight history →	SEA 10:01	SMF 12:01	28%	5%	0.6%	65%
AS 681 Alaska Flight history →	SEA 14:16	SMF 16:11	30%	8%	0.6%	84%worse than usual
AS 1428 Alaska Flight history →	SEA 11:55	SMF 13:57	32%	6%	0.6%	71%
AS 638 Alaska Flight history →	SEA 19:23	SMF 21:16	34%	9%	0.6%	75%
WN 636 Southwest Flight history →	SEA 21:40	SMF 23:40	34%	11%	0.5%	52%
AS 1427 Alaska Flight history →	SEA 20:55	SMF 22:48	36%	8%	0.6%	73%
WN 3566 Southwest Flight history →	SEA 18:05	SMF 20:05	37%	12%	0.5%	61%

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