Monday, October 5 · our forecast odds · issued Sun 9:00 PM ET · 23 nonstops

Tomorrow: WN 4920 at 05:00 is the safest bet, 9% chance of being 15+ min late; evening flights run 21–35%.

Safest bet that day WN 4920 SMF 05:00 → SEA 06:55 · 9% chance 15+ min late · usually 95% on time Riskiest AS 646 SMF 18:50 → SEA 20:45 · 35% chance 15+ min late

Against a calm day 25% average chance a nonstop arrives 15+ min late; 19% for the same flights on a calm-weather day

Every nonstop on Mon, Oct 5

12-month record →

Ranked by the chance of arriving 15+ minutes late, 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	9%	2%	0.2%	95%
WN 3972 Southwest	SMF 05:05	SEA 07:00	10%	2%	0.2%	no record
AS 1358 Alaska Flight history →	SMF 06:01	SEA 07:57	14%	3%	0.7%	78%
DL 4125 Delta flown by SkyWest Flight history →	SMF 13:00	SEA 15:09	16%	7%	0.6%	93%
AS 1409 Alaska Flight history →	SMF 06:13	SEA 08:16	16%	3%	0.7%	100%worse than usual
DL 3881 Delta flown by SkyWest Flight history →	SMF 11:34	SEA 13:45	19%	7%	0.6%	90%
WN 4985 Southwest Flight history →	SMF 21:55	SEA 23:55	21%	8%	0.6%	94%worse than usual
AS 1468 Alaska Flight history →	SMF 10:23	SEA 12:22	22%	4%	0.6%	90%worse than usual
WN 3755 Southwest	SMF 11:30	SEA 13:26	23%	5%	0.4%	no record
AS 763 Alaska	SMF 13:09	SEA 15:04	23%	4%	0.6%	no record
AS 403 Alaska Flight history →	SMF 20:34	SEA 22:39	24%	5%	0.6%	80%
AS 1365 Alaska Flight history →	SMF 11:12	SEA 13:07	24%	4%	0.6%	86%
WN 1739 Southwest Flight history →	SMF 11:00	SEA 12:55	25%	4%	0.4%	58%
DL 4075 Delta flown by SkyWest Flight history →	SMF 07:53	SEA 10:05	26%	8%	0.6%	89%worse than usual
DL 4153 Delta flown by SkyWest Flight history →	SMF 17:20	SEA 19:25	27%	7%	0.6%	85%worse than usual
DL 4043 Delta flown by SkyWest Flight history →	SMF 19:41	SEA 21:57	28%	8%	0.6%	81%
WN 555 Southwest Flight history →	SMF 19:00	SEA 21:00	33%	9%	0.5%	41%
AS 458 Alaska	SMF 08:22	SEA 10:17	33%	5%	0.6%	no record
AS 1476 Alaska Flight history →	SMF 12:57	SEA 14:56	33%	4%	0.6%	68%
AS 795 Alaska Flight history →	SMF 08:03	SEA 10:09	35%	5%	0.6%	71%
WN 3973 Southwest	SMF 18:10	SEA 20:07	35%	9%	0.5%	no record
AS 683 Alaska Flight history →	SMF 17:08	SEA 19:07	35%	5%	0.6%	60%
AS 646 Alaska	SMF 18:50	SEA 20:45	35%	5%	0.6%	no record

How these are worked out. Each flight’s odds are our forecast for that day; 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 Mon, Oct 5 (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