Today: DL 1515 at 06:00 is the safest bet, 11% chance of being 15+ min late; the others run 22–38%.

Safest bet today DL 1515 PWM 06:00 → ATL 08:45 · 11% chance 15+ min late · usually 94% on time Riskiest DL 2479 PWM 13:55 → ATL 16:46 · 38% chance 15+ min late · usually 65% on time

Against a calm day 24% average chance a nonstop arrives 15+ min late; 15% 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 1515 Delta Flight history →	PWM 06:00	ATL 08:45	11%	2%	0.6%	94%
DL 488 Delta Flight history →	PWM 18:59	ATL 21:54	22%	6%	0.9%	68%
DL 2479 Delta Flight history →	PWM 13:55	ATL 16:46	38%	6%	0.7%	65%

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