Today: WN 4017 at 06:45 is the safest bet, 5% chance of being 15+ min late; evening flights run 14–18%.

Safest bet today WN 4017 SNA 06:45 → SMF 08:24 · 5% chance 15+ min late Riskiest WN 3870 SNA 14:05 → SMF 15:40 · 35% chance 15+ min late · usually 84% on time

Against a calm day 18% average chance a nonstop arrives 15+ min late; 10% 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.


WN 4017 Southwest	SNA 06:45	SMF 08:24	5%	1%	0.7%	no record
WN 2669 Southwest Flight history →	SNA 06:45	SMF 08:25	5%	1%	0.7%	96%
WN 3868 Southwest Flight history →	SNA 08:50	SMF 10:15	11%	2%	0.7%	91%
WN 4018 Southwest	SNA 09:01	SMF 10:40	13%	2%	0.6%	no record
WN 4022 Southwest	SNA 18:40	SMF 20:20	14%	5%	0.7%	no record
WN 4023 Southwest	SNA 20:40	SMF 22:19	15%	3%	0.7%	no record
WN 3872 Southwest Flight history →	SNA 18:45	SMF 20:10	16%	5%	0.6%	76%
WN 3973 Southwest	SNA 16:08	SMF 17:47	16%	5%	0.7%	no record
WN 3873 Southwest Flight history →	SNA 20:45	SMF 22:15	16%	3%	0.7%	76%
WN 3871 Southwest Flight history →	SNA 16:30	SMF 17:55	18%	5%	0.7%	88%
WN 1105 Southwest Flight history →	SNA 10:20	SMF 11:45	19%	3%	0.6%	100%worse than usual
WN 4019 Southwest	SNA 11:46	SMF 13:25	24%	4%	0.5%	no record
WN 3001 Southwest Flight history →	SNA 11:50	SMF 13:25	26%	4%	0.6%	88%worse than usual
WN 4020 Southwest	SNA 14:13	SMF 15:51	31%	6%	0.5%	no record
WN 3870 Southwest Flight history →	SNA 14:05	SMF 15:40	35%	6%	0.6%	84%worse than usual

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