Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 5 nonstops

Fri, Oct 9: WN 4611 at 07:40 is the safest bet, 6% chance of being 15+ min late; evening flights run 28%.

Safest bet that day WN 4611 MDW 07:40 → BOS 10:55 · 6% chance 15+ min late · usually 90% on time Riskiest WN 4975 MDW 16:00 → BOS 19:20 · 28% chance 15+ min late · usually 34% 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 4611 Southwest Flight history →	MDW 07:40	BOS 10:55	6%	1%	0.6%	90%
WN 1405 Southwest Flight history →	MDW 09:20	BOS 12:40	9%	2%	0.6%	92%
WN 4716 Southwest Flight history →	MDW 12:30	BOS 15:50	21%	5%	0.6%	50%
WN 232 Southwest Flight history →	MDW 19:35	BOS 22:55	28%	7%	0.6%	39%
WN 4975 Southwest Flight history →	MDW 16:00	BOS 19:20	28%	7%	0.6%	34%

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