Schedule: the flights that flew on Sunday, Oct 25, re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4021
SCHEDULED · TYPICAL SCHEDULE
Sunday, November 1
WN 4021 · ONT → SMF
departs 2:16 PM PT · arrives 3:49 PM PT
Forecast issued Fri 5:00 PM ET · 49h before departure
Watch this flight
Odds over time
Arrive at SMF more than 15 minutes late?
35%
chance · ±2 pts
−2 pts · 24h
HOW SURE WE ARE
Moderate. The odds now blend history with early weather forecasts.
Arrive 15+ late
35%
Leave 15+ late
37%
Arrive 1h+ late
10%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
6.7d
Now
1d
12h
6h
Departs
Lands
Arrive at SMF more than 15 minutes late?
Calm-weather odds: 28% · changed −2 pts in 24h
−2 pts
35%
Yes 35%
No 65%
Leave ONT more than 15 minutes late?
Calm-weather odds: 36% · changed −3 pts in 24h
−3 pts
37%
Yes 37%
No 63%
Arrive at SMF more than an hour late?
Calm-weather odds: 6% · changed +0 pts in 24h
+0 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 SMF?
On time or early
65%
15–30 min late
13%
30 min–1 hour late
12%
1–2 hours late
7%
Over 2 hours late
3%
Cancelled
<1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
WN's recent on-time record
↑
2pm departures from ONT are often late
↑
0.3 in of rain forecast at ONT that day
↓
Sundays in November are usually quieter than average
↓
Mostly benign weather forecast at SMF
Weather at each end
ONT (origin)
Gusts 15 kt Ceiling 1,500 ft Visibility 3 mi Precip 0.32 in
SMF (destination)
Gusts 9 kt Ceiling 2,000 ft Visibility 10+ mi Precip 0.03 in
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.