Today: only flights still to leave (it’s 3:36 pm at Chicago); 7 already left

Sunday, October 4 · our forecast odds · issued Sun 3:00 PM ET · connections flying that day

Today looks rough: weather pushes the average chance of arriving 15+ min late to 57%, against 25% on a calm day. Safest: WN 3521 at 18:45, 56%.

Nonstops today


WN 3521 Southwest	MDW 18:45	BOS 22:05	56%	14%	0.2%	no record
WN 3645 Southwest	MDW 19:01	BOS 22:23	58%	14%	0.2%	no record

Best connections today, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Boston on time, from each leg’s forecast for the day. Total trip = scheduled departure to arrival (Boston is 1 h ahead of Chicago). Layovers up to 4 hours. Pick a connection for its 12-month details.


Delta Details →	MDW 17:10 → ATL 20:22DL 1728	2h 18m Atlanta	ATL 22:40 → BOS 01:20 +1DL 865	7h 10m	91%	43%
Southwest Details →	MDW 18:35 → BNA 20:05WN 1073	1h 20m Nashville	BNA 21:25 → BOS 00:55 +1WN 459	5h 20m	77%	40%

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