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 4877
SCHEDULED · TYPICAL SCHEDULE
Wednesday, September 30 Today
WN 4877 · SJC → LAX
departs 4:30 PM PT · arrives 5:50 PM PT
Forecast issued Wed 2:00 AM ET · 18h before departure
Watch this flight
Other days
Today
Thu 10/1 16%
Fri 10/2 16%
Sat 10/3 9%
Sun 10/4 12%
Mon 10/5 14%
Tue 10/6 14%
Odds over time
Arrive at LAX more than 15 minutes late?
15%
chance · ±2 pts
−2 pts · 24h
HOW SURE WE ARE
Good. The odds now lean mostly on firmed-up weather forecasts.
Arrive 15+ late
15%
Leave 15+ late
20%
Arrive 1h+ late
3%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
2.9d
2d
1d
Now
12h
6h
Departs
Lands
Arrive at LAX more than 15 minutes late?
Calm-weather odds: 14% · changed −2 pts in 24h
−2 pts
15%
Yes 15%
No 85%
Leave SJC more than 15 minutes late?
Calm-weather odds: 19% · changed +1 pt in 24h
+1 pt
20%
Yes 20%
No 80%
Arrive at LAX more than an hour late?
Calm-weather odds: 3% · changed +0 pts in 24h
+0 pts
3%
Yes 3%
No 97%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to LAX?
On time or early
84%
15–30 min late
8%
30 min–1 hour late
5%
1–2 hours late
2%
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
↑
Arrivals into LAX at that hour are often late
↑
Later flights pick up delays from earlier in the day
↑
WN's recent on-time record
↓
Wednesdays in September are usually quieter than average
↓
Cloud base down to 1,100 ft forecast at LAX that day
Weather at each end
SJC (origin)
Gusts 13 kt Ceiling none (clear) Visibility 7 mi Precip none
LAX (destination)
Gusts 11 kt Ceiling 1,100 ft Visibility 7 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.