Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 3 nonstops

Fri, Oct 9: DL 4038 at 09:40 is the safest bet, 4% chance of being 15+ min late; evening flights run 8–17%.

Safest bet that day DL 4038 SLC 09:40 → BIL 11:09 · 4% chance 15+ min late · usually 96% on time Riskiest DL 1340 SLC 21:25 → BIL 22:50 · 17% chance 15+ min late · usually 80% 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 4038 Delta flown by SkyWest Flight history →	SLC 09:40	BIL 11:09	4%	2%	0.5%	96%
DL 3828 Delta flown by SkyWest Flight history →	SLC 16:25	BIL 17:52	8%	4%	0.5%	89%
DL 1340 Delta Flight history →	SLC 21:25	BIL 22:50	17%	8%	0.6%	80%

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