Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 3 nonstops

Fri, Oct 9: WN 852 at 07:40 is the safest bet, 6% chance of being 15+ min late; the others run 16–32%.

Safest bet that day WN 852 MDW 07:40 → RDU 10:35 · 6% chance 15+ min late · usually 88% on time Riskiest WN 4221 MDW 18:55 → RDU 21:50 · 32% chance 15+ min late · usually 46% 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.


WN 852 Southwest Flight history →	MDW 07:40	RDU 10:35	6%	2%	0.7%	88%
WN 4462 Southwest Flight history →	MDW 13:20	RDU 16:15	16%	4%	0.7%	76%
WN 4221 Southwest Flight history →	MDW 18:55	RDU 21:50	32%	6%	0.7%	46%

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