Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sat 8:00 PM ET · 4 nonstops

Fri, Oct 9: UA 2129 at 21:45 is the safest bet, 14% chance of being 15+ min late; the others run 16–24%.

Safest bet that day UA 2129 SAN 21:45 → IAD 05:45 · 14% chance 15+ min late · usually 89% on time Riskiest AS 506 SAN 10:34 → IAD 18:45 · 24% chance 15+ min late · usually 86% 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.


UA 2129 United Flight history →	SAN 21:45	IAD 05:45	14%	3%	0.7%	89%
UA 1071 United Flight history →	SAN 08:00	IAD 16:08	16%	3%	0.7%	88%
UA 444 United Flight history →	SAN 12:57	IAD 21:05	21%	5%	0.6%	87%
AS 506 Alaska Flight history →	SAN 10:34	IAD 18:45	24%	5%	0.7%	86%

Alternatives with one stop that day

All connections →


Delta Details →	SAN 06:15 → DTW 13:48DL 754	1h 20m Detroit	DTW 15:08 → IAD 16:41DL 1787	7h 26m	96%	80%
United Details →	SAN 10:55 → DEN 14:27UA 1715	1h 13m Denver	DEN 15:40 → IAD 21:11UA 421	7h 16m	94%	76%
Delta Details →	SAN 13:15 → SLC 16:18DL 1296	1h 12m Salt Lake City	SLC 17:30 → IAD 23:29DL 847	7h 14m	89%	73%

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