Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 6 nonstops

Fri, Oct 9: WN 1781 at 08:40 is the safest bet, 11% chance of being 15+ min late; the others run 22–34%.

Safest bet that day WN 1781 DTW 08:40 → MDW 08:55 · 11% chance 15+ min late · usually 86% on time Riskiest WN 1782 DTW 20:30 → MDW 20:40 · 34% chance 15+ min late · usually 39% on time

Every nonstop on Fri, Oct 9

12-month record →

Ranked by the chance of arriving 15+ minutes late (typical odds: the weather this date has had in past years), 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.


WN 1781 Southwest Flight history →	DTW 08:40	MDW 08:55	11%	2%	0.6%	86%
WN 507 Southwest Flight history →	DTW 13:25	MDW 13:35	22%	4%	0.6%	31%
WN 1782 Southwest Flight history →	DTW 20:30	MDW 20:40	34%	7%	0.6%	39%
DL 4688 Delta flown by Endeavor no forecast: 12-month record	DTW 12:25	MDW 12:46	18%	8%	1.2%	82%
DL 4684 Delta flown by Endeavor no forecast: 12-month record	DTW 08:50	MDW 09:14	26%	3%	0.0%	74%
DL 4677 Delta flown by Endeavor no forecast: 12-month record	DTW 18:07	MDW 18:25	40%	24%	1.2%	60%

How these are worked out. Each flight’s odds are our forecast for that day (typical odds until the weather forecast covers it); 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 Fri, Oct 9 (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