Schedule: a typical Thursday (the flights of Jul 30, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
SOUTHWEST · FLIGHT WN 3851
SCHEDULED · TYPICAL SCHEDULE
Thursday, October 1 Tomorrow
WN 3851 · LAS → STL
departs 1:50 PM PT · arrives 7:05 PM CT
Forecast issued Wed 6:00 AM ET · 35h before departure
Watch this flight
Other days
Thu 10/1
Fri 10/2 37%
Sat 10/3 17%
Sun 10/4 32%
Mon 10/5 28%
Odds over time
Arrive at STL more than 15 minutes late?
34%
chance · ±5 pts
+3 pts · 24h
HOW SURE WE ARE
Moderate. The odds now blend history with early weather forecasts.
Arrive 15+ late
34%
Leave 15+ late
39%
Arrive 1h+ late
8%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
2.7d
2d
Now
1d
12h
6h
Departs
Lands
Arrive at STL more than 15 minutes late?
Calm-weather odds: 28% · changed +3 pts in 24h
+3 pts
34%
Yes 34%
No 66%
Leave LAS more than 15 minutes late?
Calm-weather odds: 37% · changed −3 pts in 24h
−3 pts
39%
Yes 39%
No 61%
Arrive at STL more than an hour late?
Calm-weather odds: 5% · changed +0 pts in 24h
+0 pts
8%
Yes 8%
No 92%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to STL?
On time or early
66%
15–30 min late
12%
30 min–1 hour late
13%
1–2 hours late
6%
Over 2 hours late
3%
Cancelled
<1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Cloud base down to 600 ft, 0.3 in of rain forecast at STL that day
↑
WN's recent on-time record
↑
Arrivals into STL at that hour are often late
↓
Mostly benign weather forecast at LAS
↓
STL usually runs smoothly
Weather at each end
LAS (origin)
Gusts 9 kt Ceiling none (clear) Visibility 10+ mi Precip none
STL (destination)
Gusts 16 kt Ceiling 600 ft Visibility 3 mi Precip 0.26 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.