Today: only flights still to leave (it’s 6:42 pm at Ontario)

Sunday, October 4 · our forecast odds · issued Sun 8:00 PM ET · connections flying that day

Today looks rough: weather pushes the legs’ average chance of arriving 15+ min late to 45% (calm day: 29%). Best bet: Alaska via Seattle, leaving 18:56, 47% on time.

Best connections today, one ticket

Ranked by chance you reach Dulles on time, from each leg’s forecast for the day. Total trip = scheduled departure to arrival (Dulles is 3 h ahead of Ontario). Layovers up to 4 hours. Pick a connection for its 12-month details.


Alaska Details →	ONT 18:56 → SEA 21:33AS 592	1h 10m Seattle	SEA 22:43 → IAD 06:39 +1AS 367	8h 43m	78%	47%
Tight connection: often missed
Frontier Details →	ONT 20:15 → LAS 21:35F9 4206	1h 08m Las Vegas	LAS 22:43 → IAD 06:14 +1F9 3494	6h 59m	64%	30%

How these are worked out. Each flight’s odds are our forecast for that day; 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 4 (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