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

Mon, Oct 12 looks like a normal day here: all 4 nonstops are 17–25% likely to arrive 15+ min late.

Safest bet that day UA 4821 IAH 09:44 → AMA 11:31 · 17% chance 15+ min late · usually 88% on time Riskiest UA 3878 IAH 21:21 → AMA 23:11 · 25% chance 15+ min late

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 4821 United flown by CommuteAir Flight history →	IAH 09:44	AMA 11:31	17%	5%	1.7%	88%
UA 4817 United flown by CommuteAir Flight history →	IAH 12:46	AMA 14:19	21%	6%	2.0%	83%
UA 4839 United flown by CommuteAir Flight history →	IAH 20:40	AMA 22:49	22%	10%	2.4%	84%
UA 3878 United	IAH 21:21	AMA 23:11	25%	10%	1.3%	no record

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