Today looks rough: weather pushes the average chance of arriving 15+ min late to 53%, against 28% on a calm day. Safest: UA 425 at 11:37, 31%.

Safest bet today UA 425 ATL 11:37 → IAH 12:47 · 31% chance 15+ min late · usually 89% on time Riskiest F9 4075 ATL 21:25 → IAH 22:39 · 75% chance 15+ min late · usually 63% on time

Weather 53% average chance a nonstop arrives 15+ min late; 28% 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. Dimmed: airlines we don’t forecast yet, shown with their 12-month record if they usually fly that weekday. 6 flights that already left today are not shown.


UA 425 United Flight history →	ATL 11:37	IAH 12:47	31%	7%	0.4%	89%worse than usual
DL 1601 Delta Flight history →	ATL 22:48	IAH 23:57	37%	8%	0.9%	76%worse than usual
DL 1572 Delta Flight history →	ATL 12:27	IAH 13:33	45%	9%	0.5%	86%worse than usual
DL 1223 Delta Flight history →	ATL 14:43	IAH 15:55	52%	12%	0.5%	68%worse than usual
DL 2890 Delta Flight history →	ATL 14:46	IAH 15:56	52%	11%	0.5%	69%worse than usual
UA 2376 United Flight history →	ATL 18:57	IAH 20:15	52%	10%	0.6%	60%worse than usual
DL 1131 Delta Flight history →	ATL 16:23	IAH 17:36	60%	12%	0.6%	59%worse than usual
DL 2327 Delta	ATL 19:00	IAH 20:15	60%	15%	0.6%	no record
DL 1284 Delta Flight history →	ATL 20:13	IAH 21:24	62%	14%	0.6%	73%worse than usual
F9 4075 Frontier Flight history →	ATL 21:25	IAH 22:39	75%	29%	1.4%	63%worse than usual
UA 3992 United flown by Mesa no forecast: 12-month record	ATL 15:57	IAH 17:23	28%	16%	0.0%	72%

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