Today: WN 240 at 08:00 is the safest bet, 13% chance of being 15+ min late; evening flights run 22–35%.

Safest bet today WN 240 ATL 08:00 → MDW 09:07 · 13% chance 15+ min late Riskiest F9 2779 ATL 17:08 → MDW 18:22 · 35% chance 15+ min late · usually 64% on time

Against a calm day 21% average chance a nonstop arrives 15+ min late; 17% 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. 1 flight that already left today is not shown.


WN 240 Southwest	ATL 08:00	MDW 09:07	13%	3%	0.4%	no record
DL 1063 Delta Flight history →	ATL 09:09	MDW 10:05	14%	4%	0.6%	88%
WN 2866 Southwest	ATL 14:05	MDW 15:12	16%	3%	0.7%	no record
DL 2417 Delta Flight history →	ATL 11:00	MDW 11:56	16%	4%	0.6%	88%
WN 1270 Southwest Flight history →	ATL 08:00	MDW 08:55	16%	4%	0.4%	78%
DL 1728 Delta Flight history →	ATL 15:15	MDW 16:15	20%	3%	0.8%	77%
WN 224 Southwest Flight history →	ATL 10:00	MDW 11:00	21%	3%	0.4%	89%
WN 246 Southwest	ATL 22:15	MDW 23:24	22%	5%	0.6%	no record
WN 225 Southwest Flight history →	ATL 12:30	MDW 13:25	22%	6%	0.4%	76%
WN 309 Southwest	ATL 17:58	MDW 19:05	23%	5%	0.6%	no record
DL 1076 Delta Flight history →	ATL 21:15	MDW 22:15	24%	5%	0.8%	77%
WN 241 Southwest	ATL 11:15	MDW 12:22	26%	4%	0.4%	no record
F9 2779 Frontier Flight history →	ATL 17:08	MDW 18:22	35%	13%	1.9%	64%

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