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 752 at 05:35 is the safest bet, 4% chance of being 15+ min late; evening flights run 24–30%.

Safest bet that day WN 752 BOS 05:35 → STL 07:25 · 4% chance 15+ min late · usually 100% on time Riskiest WN 754 BOS 18:50 → STL 20:55 · 30% chance 15+ min late · usually 42% 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 752 Southwest Flight history →	BOS 05:35	STL 07:25	4%	1%	0.6%	100%
AA 3814 American flown by Envoy Flight history →	BOS 07:00	STL 09:09	9%	2%	0.7%	90%
AA 4678 American flown by Republic Flight history →	BOS 17:12	STL 19:21	24%	7%	0.8%	56%
WN 4917 Southwest Flight history →	BOS 12:55	STL 14:45	25%	3%	0.5%	61%
WN 754 Southwest Flight history →	BOS 18:50	STL 20:55	30%	7%	0.5%	42%

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