Monday, October 5 · our forecast odds · issued Sun 3:00 PM ET · 9 nonstops

Tomorrow: WN 3457 at 05:30 is the safest bet, 3% chance of being 15+ min late; evening flights run 20–25%.

Safest bet that day WN 3457 MDW 05:30 → BOS 08:48 · 3% chance 15+ min late Riskiest WN 4975 MDW 16:00 → BOS 19:20 · 25% chance 15+ min late · usually 34% on time

Against a calm day 13% average chance a nonstop arrives 15+ min late; 12% for the same flights on a calm-weather day

Every nonstop on Mon, Oct 5

12-month record →

Ranked by the chance of arriving 15+ minutes late, 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 3457 Southwest	MDW 05:30	BOS 08:48	3%	1%	0.6%	no record
WN 4611 Southwest Flight history →	MDW 07:40	BOS 10:55	6%	1%	0.6%	90%
WN 4535 Southwest	MDW 07:50	BOS 11:08	7%	1%	0.5%	no record
WN 1405 Southwest Flight history →	MDW 09:20	BOS 12:40	8%	2%	0.6%	92%
WN 2842 Southwest	MDW 11:00	BOS 14:19	15%	3%	0.5%	no record
WN 4716 Southwest Flight history →	MDW 12:30	BOS 15:50	18%	3%	0.5%	50%
WN 4649 Southwest	MDW 12:45	BOS 16:04	19%	3%	0.6%	no record
WN 232 Southwest Flight history →	MDW 19:35	BOS 22:55	20%	5%	0.6%	39%
WN 4975 Southwest Flight history →	MDW 16:00	BOS 19:20	25%	6%	0.5%	34%

How these are worked out. Each flight’s odds are our forecast for that day; 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 Mon, Oct 5 (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