Today: DL 1859 at 19:29 is the safest bet, 49% chance of being 15+ min late; the others run 56–62%.

Safest bet today DL 1859 JFK 19:29 → SJU 23:53 · 49% chance 15+ min late · usually 70% on time Riskiest B6 303 JFK 20:00 → SJU 00:13 · 62% chance 15+ min late · usually 52% on time

Against a calm day 57% average chance a nonstop arrives 15+ min late; 57% 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. 7 flights that already left today are not shown.


DL 1859 Delta Flight history →	JFK 19:29	SJU 23:53	49%	14%	0.7%	70%worse than usual
B6 2903 JetBlue Flight history →	JFK 18:29	SJU 22:45	56%	24%	0.9%	60%worse than usual
B6 803 JetBlue Flight history →	JFK 17:30	SJU 21:40	61%	27%	1.0%	66%worse than usual
B6 303 JetBlue Flight history →	JFK 20:00	SJU 00:13	62%	30%	0.8%	52%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