Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · connections flying that day

Fri, Oct 9: Southwest via Denver, leaving 05:10, is the safest bet: 84% chance of reaching Chicago on time; the tightest one-ticket connections make it only 61% of the time.

Nonstops that day

All 2 nonstops →


WN 1779 Southwest Flight history →	SFO 05:50	MDW 12:00	6%	1%	0.7%	83%
WN 3649 Southwest Flight history →	SFO 23:40	MDW 05:55	36%	6%	0.6%	41%

Best connections that day, one ticket

Most reliable Quickest (80%+ on time)

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


Southwest Details →	SFO 05:00 → LAS 06:35WN 4231	1h 45m Las Vegas	LAS 08:20 → MDW 13:55WN 2271	6h 55m	100%	90%
Southwest Details →	SFO 05:10 → DEN 08:40WN 1424	1h 20m Denver	DEN 10:00 → MDW 13:25WN 755	6h 15m	96%	84%
Southwest Details →	SFO 05:30 → PHX 07:30WN 4145	2h 30m Phoenix	PHX 10:00 → MDW 15:15WN 4066	7h 45m	100%	80%
Southwest Details →	SFO 18:10 → SAN 19:45WN 4681	2h 55m San Diego	SAN 22:40 → MDW 04:40 +1WN 257	8h 30m	97%	80%
Delta Details →	SFO 06:00 → ATL 13:44DL 570	1h 31m Atlanta	ATL 15:15 → MDW 16:15DL 1728	8h 15m	96%	80%
Delta Details →	SFO 11:38 → ATL 19:27DL 693	1h 48m Atlanta	ATL 21:15 → MDW 22:15DL 1076	8h 37m	94%	75%
Delta Details →	SFO 00:35 → MSP 06:09DL 2789	46m Minneapolis	MSP 06:55 → MDW 08:37DL 4712 · flown by Endeavor	6h 02m	89%	74%
Southwest Details →	SFO 14:35 → DEN 18:10WN 3641	2h 40m Denver	DEN 20:50 → MDW 00:15 +1WN 1615	7h 40m	95%	72%
Tight connection: often missed
Southwest Details →	SFO 21:05 → LAX 22:40WN 3648	1h 15m Los Angeles	LAX 23:55 → MDW 05:55 +1WN 2413	6h 50m	65%	49%
Southwest Details →	SFO 14:00 → SAN 15:40WN 4242	1h 50m San Diego	SAN 17:30 → MDW 23:30WN 3448	7h 30m	67%	44%
Southwest Details →	SFO 13:20 → LAS 15:00WN 3644	1h 05m Las Vegas	LAS 16:05 → MDW 21:45WN 2274	6h 25m	61%	42%

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