Sunday, October 11 · typical odds for a Sunday (too early for a weather forecast) · issued Mon 12:00 AM ET · 4 nonstops

Sun, Oct 11: UA 2637 at 09:58 is the safest bet, 15% chance of being 15+ min late; the others run 18–43%.

Safest bet that day UA 2637 DEN 09:58 → GRR 14:35 · 15% chance 15+ min late · usually 88% on time Riskiest UA 2121 DEN 17:55 → GRR 22:35 · 43% chance 15+ min late · usually 71% on time

Every nonstop on Sun, Oct 11

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.


UA 2637 United Flight history →	DEN 09:58	GRR 14:35	15%	3%	0.6%	88%
F9 1248 Frontier Flight history →	DEN 10:42	GRR 15:21	18%	4%	0.7%	89%
WN 1912 Southwest	DEN 11:40	GRR 16:12	26%	4%	0.6%	no record
UA 2121 United Flight history →	DEN 17:55	GRR 22:35	43%	13%	1.2%	71%worse than usual

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 Sun, Oct 11 (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