Today looks like a normal day here: all 3 nonstops are 13–17% likely to arrive 15+ min late.

Safest bet today UA 3540 IAD 22:30 → PIT 23:36 · 13% chance 15+ min late · usually 80% on time Riskiest YX 3517 IAD 17:18 → PIT 18:32 · 17% chance 15+ min late

Against a calm day 15% average chance a nonstop arrives 15+ min late; 12% 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.


UA 3540 United flown by Republic Flight history →	IAD 22:30	PIT 23:36	13%	3%	0.7%	80%
UA 2066 United Flight history →	IAD 12:56	PIT 14:03	14%	4%	0.4%	90%
YX 3517 Republic	IAD 17:18	PIT 18:32	17%	5%	0.6%	no record
UA 6119 United flown by Mesa no forecast: 12-month record	IAD 08:30	PIT 09:40	12%	5%	0.0%	88%

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