Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Mon 12:00 PM ET · 3 nonstops

Fri, Oct 9 looks like a normal day here: all 3 nonstops are 3–7% likely to arrive 15+ min late.

Safest bet that day DL 4037 SUN 07:20 → SLC 08:27 · 3% chance 15+ min late · usually 98% on time Riskiest DL 3690 SUN 15:15 → SLC 16:24 · 7% chance 15+ min late · usually 89% on time

Every nonstop on Fri, Oct 9

12-month record →

Ranked by the chance of arriving 15+ minutes late (typical odds: the weather this date has had in past years), 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 4037 Delta flown by SkyWest Flight history →	SUN 07:20	SLC 08:27	3%	4%	0.8%	98%
DL 4019 Delta flown by SkyWest Flight history →	SUN 13:10	SLC 14:21	7%	5%	0.8%	91%
DL 3690 Delta flown by SkyWest Flight history →	SUN 15:15	SLC 16:24	7%	4%	0.8%	89%

How these are worked out. Each flight’s odds are our forecast for that day (typical odds until the weather forecast covers it); 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 Fri, Oct 9 (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