Today: WN 4002 at 12:51 is the safest bet, 17% chance of being 15+ min late; evening flights run 26–31%.

Safest bet today WN 4002 ONT 12:51 → OAK 14:18 · 17% chance 15+ min late Riskiest WN 2949 ONT 20:30 → OAK 21:50 · 31% chance 15+ min late

Against a calm day 26% average chance a nonstop arrives 15+ min late; 18% 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. 3 flights that already left today are not shown.


WN 4002 Southwest	ONT 12:51	OAK 14:18	17%	5%	0.2%	no record
WN 123 Southwest	ONT 15:51	OAK 17:18	25%	7%	0.2%	no record
WN 2667 Southwest	ONT 21:11	OAK 22:38	26%	8%	0.2%	no record
WN 3155 Southwest Flight history →	ONT 16:35	OAK 17:50	30%	8%	0.2%	79%
WN 2949 Southwest	ONT 20:30	OAK 21:50	31%	9%	0.2%	no record

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