Today looks rough: weather pushes the average chance of arriving 15+ min late to 43%, against 28% on a calm day. Safest: WN 4450 at 15:30, 35%.

Safest bet today WN 4450 MDW 15:30 → DTW 17:40 · 35% chance 15+ min late · usually 52% on time Riskiest WN 4340 MDW 19:45 → DTW 22:00 · 48% chance 15+ min late

Weather 43% average chance a nonstop arrives 15+ min late; 28% 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. Dimmed: airlines we don’t forecast yet, shown with their 12-month record if they usually fly that weekday. 5 flights that already left today are not shown.


WN 4450 Southwest Flight history →	MDW 15:30	DTW 17:40	35%	6%	0.2%	52%
WN 2906 Southwest	MDW 19:11	DTW 21:25	47%	7%	0.2%	no record
WN 4340 Southwest	MDW 19:45	DTW 22:00	48%	7%	0.2%	no record
DL 4690 Delta flown by Endeavor no forecast: 12-month record	MDW 18:58	DTW 21:16	43%	20%	1.8%	57%

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