Today: DL 497 at 07:50 is the safest bet, 11% chance of being 15+ min late; evening flights run 37%.

Safest bet today DL 497 BOS 07:50 → LAS 10:32 · 11% chance 15+ min late · usually 83% on time Riskiest B6 777 BOS 19:59 → LAS 22:47 · 37% chance 15+ min late · usually 65% on time

Against a calm day 25% average chance a nonstop arrives 15+ min late; 25% 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.


DL 497 Delta Flight history →	BOS 07:50	LAS 10:32	11%	4%	0.3%	83%
B6 1577 JetBlue Flight history →	BOS 07:08	LAS 10:01	17%	6%	0.2%	68%
B6 1177 JetBlue Flight history →	BOS 10:34	LAS 13:26	24%	7%	0.2%	87%worse than usual
B6 177 JetBlue Flight history →	BOS 18:28	LAS 21:22	37%	16%	0.6%	68%
B6 777 JetBlue Flight history →	BOS 19:59	LAS 22:47	37%	16%	0.7%	65%

Alternatives with one stop that day

All connections →


Southwest Details →	BOS 05:35 → STL 07:25WN 752	1h 50m St Louis	STL 09:15 → LAS 10:40WN 2327	8h 05m	100%	91%
Delta Details →	BOS 05:55 → MSP 08:04DL 2303	1h 09m Minneapolis	MSP 09:13 → LAS 10:31DL 2262	7h 36m	97%	90%
Delta Details →	BOS 05:30 → DTW 07:38DL 1019	1h 21m Detroit	DTW 08:59 → LAS 10:12DL 334	7h 42m	98%	86%

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