Today looks rough: weather pushes the average chance of arriving 15+ min late to 56%, against 41% on a calm day. Safest: WN 3517 at 18:15, 54%.

Safest bet today WN 3517 BWI 18:15 → PIT 19:26 · 54% chance 15+ min late Riskiest WN 2131 BWI 22:15 → PIT 23:26 · 58% chance 15+ min late

Weather 56% average chance a nonstop arrives 15+ min late; 41% 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. 2 flights that already left today are not shown.


WN 3517 Southwest	BWI 18:15	PIT 19:26	54%	12%	0.2%	no record
WN 1053 Southwest Flight history →	BWI 17:00	PIT 18:05	55%	12%	0.3%	66%worse than usual
WN 4164 Southwest Flight history →	BWI 22:50	PIT 23:55	58%	8%	0.2%	49%
WN 2131 Southwest	BWI 22:15	PIT 23:26	58%	8%	0.2%	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