Today looks like a normal day here: all 7 nonstops are 4–12% likely to arrive 15+ min late.

Safest bet today DL 2708 ONT 06:00 → SLC 08:48 · 4% chance 15+ min late · usually 95% on time Riskiest DL 3172 ONT 13:00 → SLC 15:47 · 12% chance 15+ min late · usually 95% on time

Against a calm day 9% 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 2708 Delta Flight history →	ONT 06:00	SLC 08:48	4%	1%	0.2%	95%
OO 3872 SkyWest	ONT 09:49	SLC 12:44	8%	4%	0.4%	no record
DL 1302 Delta Flight history →	ONT 09:40	SLC 12:28	8%	3%	0.2%	98%
DL 4443 Delta flown by SkyWest Flight history →	ONT 17:10	SLC 20:03	8%	3%	0.7%	87%
OO 3744 SkyWest	ONT 17:12	SLC 20:07	9%	3%	0.7%	no record
DL 1173 Delta	ONT 12:30	SLC 15:22	11%	4%	0.2%	no record
DL 3172 Delta Flight history →	ONT 13:00	SLC 15:47	12%	4%	0.2%	95%

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