Today looks like a normal day here: all 3 nonstops are 5–12% likely to arrive 15+ min late.

Safest bet today DL 3940 COS 08:10 → SLC 10:09 · 5% chance 15+ min late · usually 96% on time Riskiest DL 4449 COS 18:16 → SLC 20:09 · 12% chance 15+ min late · usually 91% on time

Against a calm day 8% average chance a nonstop arrives 15+ min late; 6% 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.


DL 3940 Delta flown by SkyWest Flight history →	COS 08:10	SLC 10:09	5%	4%	0.1%	96%
OO 117 SkyWest	COS 08:09	SLC 09:55	6%	5%	0.1%	no record
DL 4449 Delta flown by SkyWest Flight history →	COS 18:16	SLC 20:09	12%	4%	0.2%	91%

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