Thursday, October 8 · typical odds for a Thursday (too early for a weather forecast) · issued Sun 12:00 PM ET · 4 nonstops

Thu, Oct 8 looks like a normal day here: all 4 nonstops are 11–20% likely to arrive 15+ min late.

Safest bet that day F9 1248 DEN 10:47 → GRR 15:32 · 11% chance 15+ min late · usually 89% on time Riskiest UA 2121 DEN 17:55 → GRR 22:35 · 20% chance 15+ min late · usually 71% on time

Every nonstop on Thu, Oct 8

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.


F9 1248 Frontier Flight history →	DEN 10:47	GRR 15:32	11%	4%	0.6%	89%
UA 2637 United Flight history →	DEN 09:58	GRR 14:35	11%	3%	0.6%	88%
WN 3890 Southwest	DEN 10:41	GRR 15:12	15%	3%	0.6%	no record
UA 2121 United Flight history →	DEN 17:55	GRR 22:35	20%	8%	0.5%	71%

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 Thu, Oct 8 (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