Schedule: a typical summer Friday (the flights of Jul 31, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4539
SCHEDULED · TYPICAL SCHEDULE
Friday, October 2
WN 4539 · LAS → STL
departs 7:00 PM PT · arrives 12:15 AM CT
Forecast issued Fri 10:00 PM ET · 0h before departure
Watch this flight
Other days
Fri 10/2
Today 33%
Fri 10/9 38%
Odds over time
Arrive at STL more than 15 minutes late?
33%
chance · ±1 pts
+2 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
33%
Leave 15+ late
37%
Arrive 1h+ late
10%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
20%
40%
60%
80%
4d
2d
1d
12h
6h
Departs
Lands
Arrive at STL more than 15 minutes late?
Calm-weather odds: 34% · changed +2 pts in 24h
+2 pts
33%
Yes 33%
No 67%
Leave LAS more than 15 minutes late?
Calm-weather odds: 37% · changed +2 pts in 24h
+2 pts
37%
Yes 37%
No 63%
Arrive at STL more than an hour late?
Calm-weather odds: 10% · changed −1 pt in 24h
−1 pt
10%
Yes 10%
No 90%
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
67%
15–30 min late
11%
30 min–1 hour late
12%
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
↑
7pm departures from LAS are often late
↑
WN's recent on-time record
↑
Later flights pick up delays from earlier in the day
↓
Mostly benign weather forecast at LAS
↓
Fridays in October are usually quieter than average
Weather at each end
LAS (origin)
Gusts 7 kt Ceiling none (clear) Visibility 10+ mi Precip none
STL (destination)
Gusts 20 kt Ceiling 600 ft Visibility 9 mi Precip 0.01 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.