Today looks rough: weather pushes the average chance of arriving 15+ min late to 48%, against 31% on a calm day. Safest: AA 2500 at 23:55, 36%.

Safest bet today AA 2500 DEN 23:55 → PHL 05:32 · 36% chance 15+ min late · usually 78% on time Riskiest WN 3839 DEN 19:55 → PHL 01:35 · 55% chance 15+ min late

Weather 48% average chance a nonstop arrives 15+ min late; 31% 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. 15 flights that already left today are not shown.


AA 2500 American Flight history →	DEN 23:55	PHL 05:32	36%	14%	0.9%	78%worse than usual
F9 3340 Frontier Flight history →	DEN 23:59	PHL 05:39	52%	24%	2.2%	62%worse than usual
WN 3839 Southwest	DEN 19:55	PHL 01:35	55%	19%	0.4%	no record

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