Today: DL 2040 at 23:00 is the safest bet, 17% chance of being 15+ min late; the others run 28–36%.

Safest bet today DL 2040 SLC 23:00 → MIA 05:40 · 17% chance 15+ min late · usually 91% on time Riskiest AA 483 SLC 13:56 → MIA 20:52 · 36% chance 15+ min late · usually 71% on time

Against a calm day 27% average chance a nonstop arrives 15+ min late; 29% 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 2040 Delta Flight history →	SLC 23:00	MIA 05:40	17%	4%	0.4%	91%
AA 3070 American Flight history →	SLC 23:59	MIA 06:43	28%	7%	1.0%	81%
AA 483 American Flight history →	SLC 13:56	MIA 20:52	36%	6%	0.3%	71%

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