Schedule: a typical summer Friday (the flights of Jul 31, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
SOUTHWEST · FLIGHT WN 3691
SCHEDULED · TYPICAL SCHEDULE
Friday, October 2 Yesterday
WN 3691 · SJC → ONT
departs 4:40 PM PT · arrives 6:00 PM PT
Forecast issued Fri 10:00 PM ET · 2h after departure
Watch this flight
Other days
Fri 10/2
Mon 10/5 20%
Fri 10/9 27%
Odds over time
Arrive at ONT more than 15 minutes late?
24%
chance · ±1 pts
−6 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
24%
Leave 15+ late
38%
Arrive 1h+ late
10%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
3.9d
2d
1d
12h
6h
Departs
Lands
Now
Arrive at ONT more than 15 minutes late?
Calm-weather odds: 25% · changed −6 pts in 24h
−6 pts
24%
Yes 24%
No 76%
Leave SJC more than 15 minutes late?
Calm-weather odds: 38% · changed +1 pt in 24h
+1 pt
38%
Yes 38%
No 62%
Arrive at ONT more than an hour late?
Calm-weather odds: 10% · changed +2 pts in 24h
+2 pts
10%
Yes 10%
No 90%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to ONT?
On time or early
76%
15–30 min late
13%
30 min–1 hour late
<1%
1–2 hours late
7%
Over 2 hours late
4%
Cancelled
<1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Later flights pick up delays from earlier in the day
↑
WN's recent on-time record
↑
Arrivals into ONT at that hour are often late
↓
Mostly benign weather forecast at ONT
↓
Cloud base down to 700 ft forecast at SJC that day
Weather at each end
SJC (origin)
Gusts 5 kt Ceiling 700 ft Visibility 4 mi Precip none
ONT (destination)
Gusts 11 kt Ceiling none (clear) Visibility 8 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.