Today: UA 1101 at 08:00 is the safest bet, 7% chance of being 15+ min late; evening flights run 15–25%.

Safest bet today UA 1101 DEN 08:00 → IAD 13:26 · 7% chance 15+ min late · usually 94% on time Riskiest UA 1412 DEN 19:13 → IAD 00:45 · 25% chance 15+ min late · usually 73% on time

Against a calm day 16% average chance a nonstop arrives 15+ min late; 21% 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. 1 flight that already left today is not shown.


UA 1101 United Flight history →	DEN 08:00	IAD 13:26	7%	3%	0.2%	94%
UA 2087 United Flight history →	DEN 10:20	IAD 15:53	11%	4%	0.1%	81%
UA 1924 United Flight history →	DEN 23:59	IAD 05:27	15%	5%	0.6%	94%
UA 2853 United Flight history →	DEN 12:26	IAD 17:58	15%	5%	0.2%	82%
UA 347 United Flight history →	DEN 13:53	IAD 19:22	16%	6%	0.2%	87%
UA 421 United Flight history →	DEN 15:40	IAD 21:11	17%	6%	0.2%	71%
UA 2408 United Flight history →	DEN 18:00	IAD 23:32	21%	6%	0.2%	71%
UA 1412 United Flight history →	DEN 19:13	IAD 00:45	25%	9%	0.6%	73%

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