Today looks like a normal day here: all 3 nonstops are 31–32% likely to arrive 15+ min late.

Safest bet today WN 2890 MDW 17:15 → SEA 19:45 · 31% chance 15+ min late · usually 27% on time Riskiest WN 647 MDW 22:05 → SEA 00:25 · 32% chance 15+ min late

Against a calm day 32% 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. 1 flight that already left today is not shown.


WN 2890 Southwest Flight history →	MDW 17:15	SEA 19:45	31%	6%	0.1%	27%
WN 4144 Southwest Flight history →	MDW 22:00	SEA 00:35	31%	7%	0.2%	57%
WN 647 Southwest	MDW 22:05	SEA 00:25	32%	6%	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 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