Today: DL 5840 at 22:00 is the safest bet, 26% chance of being 15+ min late; the others run 35–54%.

Safest bet today DL 5840 BOS 22:00 → LGA 23:23 · 26% chance 15+ min late · usually 69% on time Riskiest DL 5716 BOS 18:59 → LGA 20:29 · 54% chance 15+ min late · usually 64% on time

Against a calm day 46% average chance a nonstop arrives 15+ min late; 48% 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. 18 flights that already left today are not shown.


DL 5840 Delta flown by Republic Flight history →	BOS 22:00	LGA 23:23	26%	11%	1.4%	69%
DL 5609 Delta flown by Republic Flight history →	BOS 21:00	LGA 22:21	35%	19%	1.3%	67%
DL 5721 Delta flown by Republic Flight history →	BOS 17:00	LGA 18:29	45%	20%	1.3%	69%worse than usual
DL 5831 Delta flown by Republic Flight history →	BOS 18:00	LGA 19:34	45%	18%	1.4%	65%worse than usual
AA 4430 American flown by Republic Flight history →	BOS 17:41	LGA 19:15	48%	18%	1.0%	60%
YX 5621 Republic	BOS 20:05	LGA 21:31	48%	19%	1.2%	no record
AA 4397 American flown by Republic Flight history →	BOS 20:00	LGA 21:26	49%	23%	1.4%	64%worse than usual
AA 4724 American flown by Republic Flight history →	BOS 19:30	LGA 20:56	51%	22%	1.3%	57%
AA 4632 American flown by Republic Flight history →	BOS 17:51	LGA 19:19	53%	20%	1.3%	49%
DL 5849 Delta flown by Republic Flight history →	BOS 20:00	LGA 21:29	53%	22%	1.3%	50%
DL 5716 Delta flown by Republic Flight history →	BOS 18:59	LGA 20:29	54%	24%	1.5%	64%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