Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 11 nonstops

Fri, Oct 9: WN 3937 at 06:50 is the safest bet, 4% chance of being 15+ min late; evening flights run 16–32%.

Safest bet that day WN 3937 ATL 06:50 → STL 07:30 · 4% chance 15+ min late · usually 96% on time Riskiest WN 241 ATL 20:20 → STL 21:00 · 32% chance 15+ min late · usually 15% 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 3937 Southwest Flight history →	ATL 06:50	STL 07:30	4%	1%	0.5%	96%
DL 1571 Delta Flight history →	ATL 07:43	STL 08:19	6%	2%	0.6%	92%
DL 1400 Delta Flight history →	ATL 09:04	STL 09:43	9%	2%	0.6%	87%
DL 566 Delta Flight history →	ATL 11:40	STL 12:17	12%	3%	0.6%	83%
DL 2700 Delta Flight history →	ATL 14:09	STL 14:48	13%	3%	0.6%	90%
DL 1403 Delta Flight history →	ATL 23:10	STL 23:53	16%	4%	0.6%	83%
DL 1393 Delta Flight history →	ATL 17:10	STL 17:53	18%	4%	0.6%	79%
DL 2833 Delta Flight history →	ATL 21:33	STL 22:15	19%	4%	0.6%	76%
WN 240 Southwest Flight history →	ATL 13:10	STL 13:50	19%	3%	0.5%	76%
F9 4473 Frontier Flight history →	ATL 08:05	STL 08:57	19%	8%	0.8%	69%
WN 241 Southwest Flight history →	ATL 20:20	STL 21:00	32%	6%	0.5%	15%

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