Schedule: a typical summer Sunday (the flights of Jul 26, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4378
SCHEDULED · TYPICAL SCHEDULE
Sunday, October 4 Today
WN 4378 · DAL → LAS
departs 10:40 PM CT · arrives 11:30 PM PT
Forecast issued Sun 5:00 AM ET · 19h before departure
Watch this flight
Other days
Today
Mon 10/5 19%
Fri 10/9 35%
Odds over time
Arrive at LAS more than 15 minutes late?
47%
chance · ±2 pts
+10 pts · 24h
HOW SURE WE ARE
Good. The odds now lean mostly on firmed-up weather forecasts.
Arrive 15+ late
47%
Leave 15+ late
58%
Arrive 1h+ late
11%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
6.1d
2d
1d
Now
12h
6h
Departs
Lands
Arrive at LAS more than 15 minutes late?
Calm-weather odds: 39% · changed +10 pts in 24h
+10 pts
47%
Yes 47%
No 53%
Leave DAL more than 15 minutes late?
Calm-weather odds: 51% · changed +4 pts in 24h
+4 pts
58%
Yes 58%
No 42%
Arrive at LAS more than an hour late?
Calm-weather odds: 8% · changed +1 pt in 24h
+1 pt
11%
Yes 11%
No 89%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to LAS?
On time or early
53%
15–30 min late
21%
30 min–1 hour late
15%
1–2 hours late
9%
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
↑
10pm departures from DAL are often late
↑
Later flights pick up delays from earlier in the day
↑
Arrivals into LAS at that hour are often late
↓
Mostly benign weather forecast at LAS
Weather at each end
DAL (origin)
Gusts 17 kt Ceiling 600 ft Visibility 10+ mi Precip 0.04 in
LAS (destination)
Gusts 14 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.