Monday, October 5 · our forecast odds · issued Sun 9:00 PM ET · 12 nonstops

Tomorrow: WN 805 at 05:50 is the safest bet, 4% chance of being 15+ min late; evening flights run 22–30%.

Safest bet that day WN 805 BOS 05:50 → MDW 07:37 · 4% chance 15+ min late Riskiest WN 4233 BOS 18:35 → MDW 20:23 · 30% chance 15+ min late

Against a calm day 18% average chance a nonstop arrives 15+ min late; 14% 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 805 Southwest	BOS 05:50	MDW 07:37	4%	1%	0.2%	no record
WN 3239 Southwest Flight history →	BOS 05:25	MDW 07:00	4%	1%	0.2%	91%
WN 1955 Southwest	BOS 07:05	MDW 08:52	8%	2%	0.2%	no record
WN 745 Southwest Flight history →	BOS 07:30	MDW 09:10	8%	2%	0.2%	91%
WN 807 Southwest	BOS 13:10	MDW 14:56	18%	3%	0.6%	no record
WN 746 Southwest Flight history →	BOS 13:10	MDW 14:45	19%	3%	0.5%	66%
WN 909 Southwest	BOS 22:00	MDW 23:48	22%	5%	0.6%	no record
WN 1383 Southwest	BOS 00:02	MDW 01:16	25%	4%	0.2%	no record
WN 4106 Southwest Flight history →	BOS 16:45	MDW 18:35	25%	6%	0.5%	54%
WN 2799 Southwest	BOS 16:50	MDW 18:38	25%	6%	0.6%	no record
WN 3911 Southwest Flight history →	BOS 18:45	MDW 20:35	28%	7%	0.6%	43%
WN 4233 Southwest	BOS 18:35	MDW 20:23	30%	6%	0.6%	no record

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