Today looks rough: weather pushes the average chance of arriving 15+ min late to 40%, against 30% on a calm day. Safest: WN 4305 at 20:11, 37%.

Safest bet today WN 4305 MDW 20:11 → DCA 23:11 · 37% chance 15+ min late Riskiest WN 1157 MDW 17:05 → DCA 19:55 · 47% chance 15+ min late · usually 37% on time

Weather 40% average chance a nonstop arrives 15+ min late; 30% 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. 8 flights that already left today are not shown.


WN 4305 Southwest	MDW 20:11	DCA 23:11	37%	11%	0.3%	no record
WN 4496 Southwest Flight history →	MDW 20:10	DCA 23:05	38%	11%	0.3%	50%
WN 1088 Southwest	MDW 16:45	DCA 19:46	38%	9%	0.3%	no record
WN 1157 Southwest Flight history →	MDW 17:05	DCA 19:55	47%	11%	0.3%	37%

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 Sun, Oct 4 (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