Today looks like a normal day here: all 3 nonstops are 18–21% likely to arrive 15+ min late.

Safest bet today WN 4110 MDW 19:05 → BUF 21:40 · 18% chance 15+ min late · usually 29% on time Riskiest WN 2846 MDW 18:40 → BUF 21:17 · 21% chance 15+ min late

Against a calm day 20% average chance a nonstop arrives 15+ min late; 23% 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. 3 flights that already left today are not shown.


WN 4110 Southwest Flight history →	MDW 19:05	BUF 21:40	18%	4%	0.2%	29%
WN 845 Southwest	MDW 13:35	BUF 15:36	20%	3%	0.1%	no record
WN 2846 Southwest	MDW 18:40	BUF 21:17	21%	4%	0.1%	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 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