Monday, October 12 · typical odds for a Monday (too early for a weather forecast) · issued Tue 12:00 AM ET · 3 nonstops

Mon, Oct 12: UA 4251 at 05:59 is the safest bet, 8% chance of being 15+ min late; the others run 8–24%.

Safest bet that day UA 4251 GSO 05:59 → IAD 07:16 · 8% chance 15+ min late · usually 91% on time Riskiest UA 4819 GSO 15:07 → IAD 16:16 · 24% chance 15+ min late · usually 75% on time

Every nonstop on Mon, Oct 12

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 4251 United flown by CommuteAir Flight history →	GSO 05:59	IAD 07:16	8%	2%	1.6%	91%
UA 3896 United	GSO 00:02	IAD 01:18	8%	4%	1.1%	no record
UA 4819 United flown by CommuteAir Flight history →	GSO 15:07	IAD 16:16	24%	4%	1.6%	75%

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 Mon, Oct 12 (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