Schedule: a typical summer Thursday (the flights of Jul 30, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4391
SCHEDULED · TYPICAL SCHEDULE
Thursday, October 1
WN 4391 · HOU → ONT
departs 7:45 AM CT · arrives 8:55 AM PT
Forecast issued Thu 10:00 PM ET · 13h after departure
Watch this flight
Other days
Thu 10/1
Mon 10/5 9%
Fri 10/9 8%
Odds over time
Arrive at ONT more than 15 minutes late?
16%
chance · ±0 pts
−1 pt · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
16%
Leave 15+ late
11%
Arrive 1h+ late
3%
Cancelled
2%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
2.8d
2d
1d
12h
6h
Departs
Lands
Arrive at ONT more than 15 minutes late?
Calm-weather odds: 16% · changed −1 pt in 24h
−1 pt
16%
Yes 16%
No 84%
Leave HOU more than 15 minutes late?
Calm-weather odds: 11% · changed −7 pts in 24h
−7 pts
11%
Yes 11%
No 89%
Arrive at ONT more than an hour late?
Calm-weather odds: 3% · changed +1 pt in 24h
+1 pt
3%
Yes 3%
No 97%
Cancelled?
Calm-weather odds: 2% · changed +1 pt in 24h
+1 pt
2%
Yes 2%
No 98%
How late will it get to ONT?
On time or early
82%
15–30 min late
8%
30 min–1 hour late
4%
1–2 hours late
2%
Over 2 hours late
<1%
Cancelled
2%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Mostly benign weather forecast at HOU
↑
HOU is prone to delays
↑
This flight has been late 22% of the time recently
↓
Early flights usually leave on time
↓
7am departures from HOU are usually not late
Weather at each end
HOU (origin)
Gusts 27 kt Ceiling 2,500 ft Visibility 1.75 mi Precip 0.73 in
ONT (destination)
Gusts 18 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.