Today: WN 3103 at 05:45 is the safest bet, 11% chance of being 15+ min late; evening flights run 33–35%.

Safest bet today WN 3103 MDW 05:45 → SAN 07:50 · 11% chance 15+ min late · usually 94% on time Riskiest WN 4285 MDW 21:25 → SAN 23:32 · 35% chance 15+ min late

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.


WN 3103 Southwest Flight history →	MDW 05:45	SAN 07:50	11%	2%	0.3%	94%
WN 2978 Southwest	MDW 05:25	SAN 07:36	11%	2%	0.3%	no record
WN 2883 Southwest Flight history →	MDW 14:15	SAN 16:25	27%	5%	0.6%	23%
WN 2980 Southwest	MDW 14:55	SAN 17:04	31%	5%	0.6%	no record
WN 2884 Southwest Flight history →	MDW 21:10	SAN 23:30	33%	5%	0.7%	52%
WN 2979 Southwest	MDW 09:40	SAN 11:50	35%	8%	0.3%	no record
WN 4285 Southwest	MDW 21:25	SAN 23:32	35%	5%	0.7%	no record

Alternatives with one stop that day

All connections →


Southwest Details →	MDW 05:20 → PHX 06:55WN 2858	1h 00m Phoenix	PHX 07:55 → SAN 09:10WN 2771	5h 50m	92%	71%
Southwest Details →	MDW 07:10 → PHX 08:45WN 2520	1h 05m Phoenix	PHX 09:50 → SAN 11:12WN 1434	6h 02m	93%	58%
Southwest Details →	MDW 16:05 → MCI 17:30WN 2812	1h 00m Kansas City	MCI 18:30 → SAN 19:50WN 4457	5h 45m	81%	54%

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