Schedule: a typical summer Monday (the flights of Jul 27, 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
Monday, October 5 Tomorrow
WN 4539 · LAS → STL
departs 7:00 PM PT · arrives 12:15 AM CT
Forecast issued Sun 9:00 AM ET · 37h before departure
Watch this flight
Other days
Mon 10/5
Fri 10/9 38%
Odds over time
Arrive at STL more than 15 minutes late?
26%
chance · ±8 pts
+1 pt · 24h
HOW SURE WE ARE
Moderate. The odds now blend history with early weather forecasts.
Arrive 15+ late
26%
Leave 15+ late
28%
Arrive 1h+ late
7%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
6.9d
2d
Now
1d
12h
6h
Departs
Lands
Arrive at STL more than 15 minutes late?
Calm-weather odds: 23% · changed +1 pt in 24h
+1 pt
26%
Yes 26%
No 74%
Leave LAS more than 15 minutes late?
Calm-weather odds: 28% · changed +1 pt in 24h
+1 pt
28%
Yes 28%
No 72%
Arrive at STL more than an hour late?
Calm-weather odds: 6% · changed +1 pt in 24h
+1 pt
7%
Yes 7%
No 93%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 100%
How late will it get to STL?
On time or early
74%
15–30 min late
8%
30 min–1 hour late
10%
1–2 hours late
6%
Over 2 hours late
1%
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
↓
Mondays in October are usually quieter than average
↓
Mostly benign weather forecast at STL
Weather at each end
LAS (origin)
Gusts 10 kt Ceiling none (clear) Visibility 10+ mi Precip none
STL (destination)
Gusts 9 kt Ceiling none (clear) Visibility 10+ mi Precip none
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.