Monday, October 5 · our forecast odds · issued Sun 9:00 PM ET · 5 nonstops

Tomorrow: WN 4256 at 06:45 is the safest bet, 4% chance of being 15+ min late; the others run 6–28%.

Safest bet that day WN 4256 COS 06:45 → PHX 07:35 · 4% chance 15+ min late · usually 96% on time Riskiest WN 1230 COS 14:35 → PHX 15:25 · 28% chance 15+ min late · usually 50% on time

Against a calm day 18% average chance a nonstop arrives 15+ min late; 17% for the same flights on a calm-weather day

Every nonstop on Mon, Oct 5

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 4256 Southwest Flight history →	COS 06:45	PHX 07:35	4%	1%	0.1%	96%
WN 1290 Southwest	COS 07:10	PHX 08:02	6%	1%	0.1%	no record
WN 3896 Southwest	COS 14:30	PHX 15:22	25%	6%	0.5%	no record
WN 1231 Southwest Flight history →	COS 21:05	PHX 21:55	26%	9%	0.6%	65%
WN 1230 Southwest Flight history →	COS 14:35	PHX 15:25	28%	6%	0.5%	50%

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