Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 7 nonstops

Fri, Oct 9: DL 5800 at 18:00 is the safest bet, 8% chance of being 15+ min late; the others run 17–20%.

Safest bet that day DL 5800 DTW 18:00 → GRR 19:01 · 8% chance 15+ min late · usually 93% on time Riskiest DL 4081 DTW 20:00 → GRR 21:00 · 20% 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. Dimmed: airlines we don’t forecast yet, shown with their 12-month record if they usually fly that weekday.


DL 5800 Delta flown by Republic Flight history →	DTW 18:00	GRR 19:01	8%	4%	0.6%	93%
DL 3500 Delta flown by SkyWest Flight history →	DTW 08:50	GRR 09:54	17%	6%	0.6%	74%
DL 4081 Delta flown by SkyWest Flight history →	DTW 20:00	GRR 21:00	20%	7%	0.6%	80%
DL 4880 Delta flown by Endeavor no forecast: 12-month record	DTW 22:55	GRR 23:57	21%	9%	2.8%	79%
DL 5390 Delta flown by Endeavor no forecast: 12-month record	DTW 12:56	GRR 13:55	31%	13%	0.0%	69%
DL 5473 Delta flown by Endeavor no forecast: 12-month record	DTW 10:21	GRR 11:21	31%	22%	1.9%	69%
DL 5511 Delta flown by Endeavor no forecast: 12-month record	DTW 16:11	GRR 17:14	42%	17%	2.0%	58%

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