Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 3 nonstops

Fri, Oct 9: UA 3421 at 10:05 is the safest bet, 7% chance of being 15+ min late; evening flights run 19–23%.

Safest bet that day UA 3421 EWR 10:05 → SDF 12:21 · 7% chance 15+ min late · usually 87% on time Riskiest UA 3512 EWR 20:25 → SDF 22:50 · 23% chance 15+ min late · usually 56% 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.


UA 3421 United flown by Republic Flight history →	EWR 10:05	SDF 12:21	7%	2%	0.9%	87%
UA 3415 United flown by Republic Flight history →	EWR 18:00	SDF 20:25	19%	6%	1.4%	85%
UA 3512 United flown by Republic Flight history →	EWR 20:25	SDF 22:50	23%	7%	1.7%	56%

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