Today looks like a normal day here: all 4 nonstops are 15–20% likely to arrive 15+ min late.

Safest bet today UA 4304 IAD 22:10 → TYS 23:49 · 15% chance 15+ min late · usually 76% on time Riskiest G4 3040 IAD 15:16 → TYS 16:42 · 20% chance 15+ min late

Against a calm day 17% average chance a nonstop arrives 15+ min late; 16% 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 4304 United flown by CommuteAir Flight history →	IAD 22:10	TYS 23:49	15%	9%	1.4%	76%
YV 4070 Mesa	IAD 14:50	TYS 16:14	17%	9%	0.7%	no record
UA 4914 United flown by CommuteAir Flight history →	IAD 18:50	TYS 20:39	17%	12%	1.3%	75%
G4 3040 Allegiant	IAD 15:16	TYS 16:42	20%	6%	0.7%	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 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