Today looks rough: weather pushes the average chance of arriving 15+ min late to 51%, against 34% on a calm day. Safest: UA 2820 at 20:05, 40%.

Safest bet today UA 2820 ORD 20:05 → SEA 22:56 · 40% chance 15+ min late · usually 59% on time Riskiest AA 2392 ORD 18:51 → SEA 21:48 · 60% chance 15+ min late

Weather 51% average chance a nonstop arrives 15+ min late; 34% 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. 14 flights that already left today are not shown.


UA 2820 United Flight history →	ORD 20:05	SEA 22:56	40%	7%	0.3%	59%
AA 3231 American	ORD 21:35	SEA 00:23	42%	7%	0.6%	no record
UA 1801 United Flight history →	ORD 16:20	SEA 19:06	45%	7%	0.2%	73%worse than usual
UA 2211 United Flight history →	ORD 20:07	SEA 22:28	48%	8%	0.3%	59%
AS 407 Alaska Flight history →	ORD 15:43	SEA 18:22	49%	8%	1.1%	68%worse than usual
AS 329 Alaska Flight history →	ORD 20:20	SEA 23:04	50%	7%	1.2%	67%worse than usual
DL 637 Delta Flight history →	ORD 17:55	SEA 20:34	56%	9%	0.4%	60%worse than usual
DL 1205 Delta	ORD 17:48	SEA 20:15	58%	9%	0.4%	no record
AS 579 Alaska Flight history →	ORD 19:16	SEA 21:42	58%	8%	1.1%	86%worse than usual
AS 337 Alaska Flight history →	ORD 17:42	SEA 20:21	58%	10%	1.3%	49%
AA 2392 American	ORD 18:51	SEA 21:48	60%	9%	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 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