Today looks rough: weather pushes the average chance of arriving 15+ min late to 76%, against 27% on a calm day. Safest: DL 865 at 22:40, 67%.

Safest bet today DL 865 ATL 22:40 → BOS 01:20 · 67% chance 15+ min late · usually 80% on time Riskiest DL 821 ATL 18:37 → BOS 21:06 · 83% chance 15+ min late · usually 69% on time

Weather 76% average chance a nonstop arrives 15+ min late; 27% 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. 14 flights that already left today are not shown.


DL 865 Delta Flight history →	ATL 22:40	BOS 01:20	67%	32%	0.6%	80%worse than usual
DL 2269 Delta Flight history →	ATL 20:50	BOS 23:36	72%	38%	0.6%	63%worse than usual
DL 300 Delta Flight history →	ATL 21:00	BOS 23:29	75%	41%	0.6%	70%worse than usual
DL 457 Delta	ATL 19:57	BOS 22:26	81%	49%	0.5%	no record
DL 821 Delta Flight history →	ATL 18:37	BOS 21:06	83%	57%	0.6%	69%worse than usual

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 Sun, Oct 4 (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