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 5631 at 06:45 is the safest bet, 5% chance of being 15+ min late; evening flights run 17–18%.

Safest bet that day DL 5631 IND 06:45 → BOS 09:10 · 5% chance 15+ min late · usually 94% on time Riskiest AA 4726 IND 18:35 → BOS 20:59 · 18% chance 15+ min late · usually 70% 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 5631 Delta flown by Republic Flight history →	IND 06:45	BOS 09:10	5%	1%	0.6%	94%
AA 4716 American flown by Republic Flight history →	IND 09:00	BOS 11:22	6%	2%	0.6%	88%
DL 5628 Delta flown by Republic Flight history →	IND 11:00	BOS 13:26	8%	2%	0.6%	91%
G4 589 Allegiant Flight history →	IND 08:30	BOS 10:44	10%	3%	0.7%	94%
AA 4368 American flown by Republic Flight history →	IND 14:45	BOS 17:16	14%	6%	0.6%	76%
DL 5647 Delta flown by Republic Flight history →	IND 18:00	BOS 20:34	17%	7%	0.7%	60%
AA 4726 American flown by Republic Flight history →	IND 18:35	BOS 20:59	18%	7%	0.7%	70%

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