Today looks rough: weather pushes the average chance of arriving 15+ min late to 58%, against 36% on a calm day. Safest: DL 2635 at 21:39, 45%.

Safest bet today DL 2635 SEA 21:39 → SFO 23:59 · 45% chance 15+ min late · usually 71% on time Riskiest AS 688 SEA 13:52 → SFO 15:59 · 75% chance 15+ min late · usually 55% on time

Weather 58% average chance a nonstop arrives 15+ min late; 36% for the same flights on a calm-weather day

Every nonstop today

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. 11 flights that already left today are not shown.


DL 2635 Delta Flight history →	SEA 21:39	SFO 23:59	45%	14%	0.3%	71%worse than usual
OO 5415 SkyWest	SEA 20:39	SFO 23:21	51%	15%	0.4%	no record
UA 737 United Flight history →	SEA 19:28	SFO 22:03	52%	19%	0.3%	56%
UA 5592 United flown by SkyWest Flight history →	SEA 17:20	SFO 19:50	53%	15%	0.4%	60%worse than usual
AS 411 Alaska Flight history →	SEA 21:42	SFO 23:59	54%	11%	0.7%	64%worse than usual
DL 3991 Delta flown by SkyWest Flight history →	SEA 17:50	SFO 20:16	55%	17%	0.4%	65%worse than usual
OO 5841 SkyWest	SEA 17:24	SFO 19:38	55%	16%	0.4%	no record
DL 3707 Delta flown by SkyWest Flight history →	SEA 14:30	SFO 16:49	56%	14%	0.5%	71%worse than usual
UA 2241 United Flight history →	SEA 18:48	SFO 21:05	58%	19%	0.3%	22%
AS 619 Alaska Flight history →	SEA 18:36	SFO 20:48	58%	14%	0.7%	29%
AS 410 Alaska	SEA 21:34	SFO 23:44	58%	12%	0.7%	no record
UA 2478 United	SEA 15:15	SFO 17:26	60%	17%	0.4%	no record
UA 2281 United	SEA 13:23	SFO 15:51	60%	15%	0.4%	no record
AS 590 Alaska Flight history →	SEA 20:42	SFO 22:55	60%	14%	0.7%	57%worse than usual
AS 628 Alaska Flight history →	SEA 19:42	SFO 21:54	60%	14%	0.7%	12%
AS 1385 Alaska Flight history →	SEA 16:36	SFO 18:48	64%	14%	0.8%	71%worse than usual
AS 655 Alaska Flight history →	SEA 11:42	SFO 14:04	68%	12%	0.9%	70%worse than usual
AS 680 Alaska Flight history →	SEA 15:44	SFO 17:52	69%	15%	0.8%	69%worse than usual
AS 688 Alaska Flight history →	SEA 13:52	SFO 15:59	75%	14%	0.9%	55%worse than usual

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 Sun, Oct 4 (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