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 4920 at 05:00 is the safest bet, 3% chance of being 15+ min late; evening flights run 24–43%.

Safest bet that day WN 4920 SMF 05:00 → SEA 06:55 · 3% chance 15+ min late · usually 95% on time Riskiest WN 555 SMF 19:00 → SEA 21:00 · 43% chance 15+ min late · usually 41% 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 4920 Southwest Flight history →	SMF 05:00	SEA 06:55	3%	1%	0.5%	95%
AS 1409 Alaska Flight history →	SMF 06:13	SEA 08:16	8%	2%	0.6%	100%
DL 4125 Delta flown by SkyWest Flight history →	SMF 13:00	SEA 15:09	14%	6%	0.5%	93%
DL 3881 Delta flown by SkyWest Flight history →	SMF 11:34	SEA 13:45	15%	5%	0.5%	90%
AS 1468 Alaska Flight history →	SMF 10:23	SEA 12:22	20%	4%	0.6%	90%worse than usual
WN 1739 Southwest Flight history →	SMF 11:00	SEA 12:55	22%	5%	0.5%	58%
DL 4075 Delta flown by SkyWest Flight history →	SMF 07:53	SEA 10:05	23%	4%	0.5%	89%worse than usual
DL 4153 Delta flown by SkyWest Flight history →	SMF 17:20	SEA 19:25	24%	8%	0.6%	85%
AS 1476 Alaska Flight history →	SMF 12:57	SEA 14:56	31%	5%	0.6%	68%
DL 4043 Delta flown by SkyWest Flight history →	SMF 19:41	SEA 21:57	32%	8%	0.6%	81%worse than usual
WN 4985 Southwest Flight history →	SMF 21:55	SEA 23:55	32%	15%	0.6%	94%worse than usual
AS 795 Alaska Flight history →	SMF 08:03	SEA 10:09	35%	4%	0.6%	71%
AS 403 Alaska Flight history →	SMF 20:34	SEA 22:39	35%	10%	0.7%	80%worse than usual
AS 683 Alaska Flight history →	SMF 17:08	SEA 19:07	39%	9%	0.7%	60%
WN 555 Southwest Flight history →	SMF 19:00	SEA 21:00	43%	17%	0.6%	41%

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