Schedule: a typical Friday (the flights of Jul 31, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.

SOUTHWEST · FLIGHT WN 3979 SCHEDULED · TYPICAL SCHEDULE

Friday, October 2

WN 3979 · STL → SAT

departs 10:15 PM CT · arrives 12:25 AM CT

Forecast issued Wed 6:00 PM ET · 53h before departure

Arrive at SAT more than 15 minutes late?

39% chance · ±8 pts – · 24h

HOW SURE WE ARE Moderate. The odds now blend history with early weather forecasts.

How late will it get to SAT?

On time or early
61%
15–30 min late
13%
30 min–1 hour late
16%
1–2 hours late
8%
Over 2 hours late
2%
Cancelled
<1%

Gate arrival compared with the scheduled arrival. The ranges add up to 100%.

What’s moving the odds

↑ Cloud base down to 300 ft, 1.7 in of rain, thunderstorms forecast at SAT that day

↑ 10pm departures from STL are often late

↑ Later flights pick up delays from earlier in the day

↓ Fridays in October are usually quieter than average

↓ STL is quiet at that time

Weather at each end

STL (origin) Gusts18 kt Ceiling700 ft Visibility7 mi Precip0.46 in

SAT (destination) Gusts13 kt Ceiling300 ft Visibility3 mi Precip1.70 in

How this resolves

Yes if the gate arrival is more than 15 minutes after the scheduled arrival. Cancelled or diverted flights resolve N/A.

Every question here is display only — there is no betting or money involved. Gate times come from the airline; a cancellation resolves only the “Cancelled?” question, and a diversion voids the delay questions.

WN 3979 · STL → SAT

Odds over time

How late will it get to SAT?