Today looks rough: weather pushes the average chance of arriving 15+ min late to 19%, against 6% on a calm day. Safest: YX 3525 at 08:35, 17%.

Safest bet today YX 3525 IAD 08:35 → SDF 10:31 · 17% chance 15+ min late Riskiest UA 3526 IAD 08:31 → SDF 10:23 · 21% chance 15+ min late · usually 91% on time

Weather 19% average chance a nonstop arrives 15+ min late; 6% 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. Dimmed: airlines we don’t forecast yet, shown with their 12-month record if they usually fly that weekday.


YX 3525 Republic	IAD 08:35	SDF 10:31	17%	11%	0.9%	no record
UA 3526 United flown by Republic Flight history →	IAD 08:31	SDF 10:23	21%	10%	1.0%	91%worse than usual
UA 3980 United flown by Mesa no forecast: 12-month record	IAD 12:48	SDF 14:37	18%	6%	0.4%	82%

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