Thursday, October 8 · typical odds for a Thursday (too early for a weather forecast) · issued Sun 12:00 PM ET · connections flying that day

Thu, Oct 8: one nonstop, UA 2021 at 08:34, with a 13% chance of arriving 15+ min late.

Nonstops that day

All 1 nonstop →


UA 2021 United Flight history →	IAD 08:34	SJU 12:34	13%	3%	0.6%	85%

Best connections that day, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach San Juan on time, from each leg’s forecast for the day. Total trip = scheduled departure to arrival. Layovers up to 4 hours. Pick a connection for its 12-month details.


Delta Details →	IAD 06:00 → ATL 07:43DL 2127	2h 02m Atlanta	ATL 09:45 → SJU 13:32DL 1882	7h 32m	98%	87%
Delta Details →	IAD 08:27 → ATL 10:18DL 3080	2h 42m Atlanta	ATL 13:00 → SJU 16:39DL 1946	8h 12m	98%	84%
Delta Details →	IAD 15:02 → ATL 16:53DL 2135	1h 52m Atlanta	ATL 18:45 → SJU 22:29DL 1861	7h 27m	94%	80%
Frontier Details →	IAD 07:49 → ATL 09:59F9 4707	2h 33m Atlanta	ATL 12:32 → SJU 16:25F9 2082	8h 36m	97%	70%
American Details →	IAD 06:14 → DFW 08:35AA 2617	51m Dallas-Fort Worth	DFW 09:26 → SJU 15:31AA 702	9h 17m	90%	70%

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