Today looks rough: weather pushes the average chance of arriving 15+ min late to 51%, against 39% on a calm day. Safest: DL 1961 at 17:50, 42%.

Safest bet today DL 1961 SJU 17:50 → JFK 22:04 · 42% chance 15+ min late · usually 87% on time Riskiest B6 304 SJU 18:30 → JFK 22:28 · 55% chance 15+ min late · usually 71% on time

Weather 51% average chance a nonstop arrives 15+ min late; 39% 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. 6 flights that already left today are not shown.


DL 1961 Delta Flight history →	SJU 17:50	JFK 22:04	42%	27%	6.5%	87%worse than usual
B6 504 JetBlue Flight history →	SJU 20:10	JFK 00:07	54%	38%	3.0%	72%worse than usual
B6 704 JetBlue Flight history →	SJU 22:35	JFK 02:29	54%	30%	2.7%	54%
B6 304 JetBlue Flight history →	SJU 18:30	JFK 22:28	55%	36%	5.7%	71%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