Schedule: a typical Wednesday (the flights of Jul 29, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4177
SCHEDULED · TYPICAL SCHEDULE
Wednesday, September 30 Today
WN 4177 · LAS → SMF
departs 3:15 PM PT · arrives 4:50 PM PT
Forecast issued Wed 6:00 AM ET · 12h before departure
Watch this flight
Other days
Today
Sat 10/3 20%
Tue 10/6 10%
Odds over time
Arrive at SMF more than 15 minutes late?
30%
chance · ±2 pts
+11 pts · 24h
HOW SURE WE ARE
Good. The odds now lean mostly on firmed-up weather forecasts.
Arrive 15+ late
30%
Leave 15+ late
34%
Arrive 1h+ late
4%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
2.9d
2d
1d
Now
6h
Departs
Lands
Arrive at SMF more than 15 minutes late?
Calm-weather odds: 28% · changed +11 pts in 24h
+11 pts
30%
Yes 30%
No 70%
Leave LAS more than 15 minutes late?
Calm-weather odds: 33% · changed +5 pts in 24h
+5 pts
34%
Yes 34%
No 66%
Arrive at SMF more than an hour late?
Calm-weather odds: 3% · changed +0 pts in 24h
+0 pts
4%
Yes 4%
No 96%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to SMF?
On time or early
70%
15–30 min late
15%
30 min–1 hour late
10%
1–2 hours late
3%
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
↑
3pm departures from LAS are often late
↑
LAS is prone to delays
↑
LAS is busy at that time
↓
Wednesdays in September are usually quieter than average
↓
Mostly benign weather forecast at SMF
Weather at each end
LAS (origin)
Gusts 16 kt Ceiling none (clear) Visibility 10+ mi Precip none
SMF (destination)
Gusts 6 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.