Today: DL 1178 at 07:25 is the safest bet, 14% chance of being 15+ min late; evening flights run 16–44%.

Safest bet today DL 1178 ATL 07:25 → ORD 08:35 · 14% chance 15+ min late · usually 88% on time Riskiest F9 1595 ATL 18:23 → ORD 19:53 · 44% chance 15+ min late · usually 57% on time

Against a calm day 26% average chance a nonstop arrives 15+ min late; 22% 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.


DL 1178 Delta Flight history →	ATL 07:25	ORD 08:35	14%	3%	0.6%	88%
DL 1199 Delta Flight history →	ATL 22:40	ORD 23:53	16%	5%	0.8%	71%
AA 616 American Flight history →	ATL 07:25	ORD 08:45	17%	6%	0.6%	75%
AA 3040 American	ATL 07:38	ORD 08:49	18%	5%	0.7%	no record
UA 1239 United Flight history →	ATL 11:29	ORD 12:52	19%	5%	0.7%	82%
DL 1147 Delta Flight history →	ATL 09:02	ORD 10:10	20%	4%	0.7%	80%
UA 745 United Flight history →	ATL 13:18	ORD 14:41	20%	4%	0.6%	81%
DL 1477 Delta Flight history →	ATL 13:02	ORD 14:14	21%	3%	0.8%	76%
AA 1363 American Flight history →	ATL 12:13	ORD 13:30	22%	5%	1.0%	75%
DL 2738 Delta Flight history →	ATL 15:50	ORD 17:12	23%	4%	0.8%	62%
UA 364 United Flight history →	ATL 10:05	ORD 11:28	23%	4%	0.6%	79%
UA 1955 United	ATL 07:54	ORD 09:08	24%	4%	0.5%	no record
AA 1153 American	ATL 13:00	ORD 14:11	24%	5%	1.3%	no record
UA 785 United Flight history →	ATL 20:44	ORD 21:59	25%	5%	0.6%	56%
UA 516 United Flight history →	ATL 15:30	ORD 16:57	25%	4%	0.6%	74%
AA 4759 American flown by Republic Flight history →	ATL 15:27	ORD 16:55	25%	5%	0.9%	58%
AA 2910 American	ATL 14:52	ORD 16:03	25%	6%	1.2%	no record
UA 1288 United	ATL 11:14	ORD 12:29	26%	4%	0.5%	no record
UA 1046 United Flight history →	ATL 18:57	ORD 20:23	27%	6%	0.6%	63%
DL 2894 Delta Flight history →	ATL 11:22	ORD 12:34	28%	4%	0.7%	70%
UA 2657 United	ATL 19:06	ORD 20:20	28%	6%	0.7%	no record
DL 2486 Delta Flight history →	ATL 19:15	ORD 20:33	28%	5%	0.8%	66%
AA 1138 American	ATL 16:44	ORD 17:57	30%	6%	1.2%	no record
UA 1850 United	ATL 17:04	ORD 18:17	30%	5%	0.7%	no record
F9 1441 Frontier Flight history →	ATL 06:35	ORD 07:53	31%	9%	1.1%	73%
AA 1041 American	ATL 10:54	ORD 12:07	31%	6%	0.6%	no record
DL 1139 Delta Flight history →	ATL 19:39	ORD 20:51	31%	6%	0.8%	60%
AA 1372 American Flight history →	ATL 19:53	ORD 21:30	31%	6%	0.9%	43%
DL 2879 Delta Flight history →	ATL 17:20	ORD 18:45	33%	5%	0.8%	49%
AA 3033 American	ATL 19:25	ORD 20:38	37%	8%	1.2%	no record
F9 1595 Frontier Flight history →	ATL 18:23	ORD 19:53	44%	14%	1.8%	57%

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