Today: UA 2131 at 19:41 is the safest bet, 26% chance of being 15+ min late; the others run 26–52%.

Safest bet today UA 2131 ATL 19:41 → IAD 21:43 · 26% chance 15+ min late Riskiest F9 3692 ATL 22:28 → IAD 00:33 · 52% chance 15+ min late · usually 56% on time

Against a calm day 32% average chance a nonstop arrives 15+ min late; 26% 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. 10 flights that already left today are not shown.


UA 2131 United	ATL 19:41	IAD 21:43	26%	6%	0.2%	no record
DL 1309 Delta Flight history →	ATL 19:15	IAD 21:03	26%	5%	0.2%	76%
DL 2549 Delta Flight history →	ATL 22:53	IAD 00:41	26%	5%	0.2%	75%
UA 2634 United Flight history →	ATL 19:32	IAD 21:30	28%	5%	0.2%	77%
F9 3692 Frontier Flight history →	ATL 22:28	IAD 00:33	52%	24%	0.8%	56%

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