Today: WN 846 at 07:45 is the safest bet, 7% chance of being 15+ min late; evening flights run 16–19%.

Safest bet today WN 846 MDW 07:45 → PIT 10:15 · 7% chance 15+ min late · usually 97% on time Riskiest WN 4211 MDW 18:50 → PIT 21:15 · 19% chance 15+ min late · usually 54% on time

Against a calm day 12% average chance a nonstop arrives 15+ min late; 10% for the same flights on a calm-weather day

Every nonstop today

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 846 Southwest Flight history →	MDW 07:45	PIT 10:15	7%	1%	0.1%	97%
WN 2963 Southwest	MDW 07:45	PIT 10:16	7%	1%	0.1%	no record
WN 2964 Southwest	MDW 13:20	PIT 15:51	11%	2%	0.1%	no record
WN 2866 Southwest Flight history →	MDW 13:35	PIT 16:00	11%	2%	0.1%	76%
WN 4803 Southwest	MDW 19:38	PIT 22:09	16%	4%	0.6%	no record
WN 4211 Southwest Flight history →	MDW 18:50	PIT 21:15	19%	4%	0.5%	54%

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