Today: only flights still to leave (it’s 4:28 pm at Chicago); 2 already left

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

Today looks rough: weather pushes the legs’ average chance of arriving 15+ min late to 41% (calm day: 27%). Best bet: Southwest via Boise, leaving 17:45, 49% on time.

Nonstops today


WN 4121 Southwest Flight history →	MDW 21:50	SMF 00:20	42%	8%	0.1%	42%
WN 2994 Southwest	MDW 21:36	SMF 00:12	45%	8%	0.1%	no record

Best connections today, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Sacramento on time, from each leg’s forecast for the day. Total trip = scheduled departure to arrival (Sacramento is 2 h behind Chicago). Layovers up to 4 hours. Pick a connection for its 12-month details.


Southwest Details →	MDW 18:30 → PHX 20:10WN 2862	2h 42m Phoenix	PHX 22:52 → SMF 00:58 +1WN 1557	8h 28m	96%	51%
Southwest Details →	MDW 17:45 → BOI 20:20WN 2737	1h 25m Boise	BOI 21:45 → SMF 22:25WN 717	6h 40m	76%	49%
Tight connection: often missed
Southwest Details →	MDW 18:30 → LAX 20:50WN 188	1h 21m Los Angeles	LAX 22:11 → SMF 23:41WN 3295	7h 11m	67%	22%

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