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 3151
SCHEDULED · TYPICAL SCHEDULE
Sunday, October 4 Tomorrow
WN 3151 · SJC → ONT
departs 11:05 AM PT · arrives 12:20 PM PT
Forecast issued Sat 10:00 PM ET · 16h before departure
Watch this flight
Other days
Sat 10/3 9%
Today
Mon 10/5 12%
Fri 10/9 11%
Odds over time
Arrive at ONT more than 15 minutes late?
11%
chance · ±0 pts
+2 pts · 24h
HOW SURE WE ARE
Good. The odds now lean mostly on firmed-up weather forecasts.
Arrive 15+ late
11%
Leave 15+ late
13%
Arrive 1h+ late
3%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
5%
10%
15%
20%
5.7d
2d
1d
Now
12h
6h
Departs
Lands
Arrive at ONT more than 15 minutes late?
Calm-weather odds: 9% · changed +2 pts in 24h
+2 pts
11%
Yes 11%
No 89%
Leave SJC more than 15 minutes late?
Calm-weather odds: 12% · changed +2 pts in 24h
+2 pts
13%
Yes 13%
No 87%
Arrive at ONT 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 100%
How late will it get to ONT?
On time or early
89%
15–30 min late
5%
30 min–1 hour late
2%
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
↑
Other factors
↑
SJC is prone to delays
↓
Mostly benign weather forecast at SJC
↓
Mostly benign weather forecast at ONT
Weather at each end
SJC (origin)
Gusts 14 kt Ceiling none (clear) Visibility 10+ mi Precip none
ONT (destination)
Gusts 17 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.