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 4021
SCHEDULED · TYPICAL SCHEDULE
Wednesday, September 30 Yesterday
WN 4021 · DEN → HOU
departs 6:05 AM MT · arrives 9:35 AM CT
Forecast issued Wed 10:00 PM ET · 14h after departure
Watch this flight
Other days
Wed 9/30
Sun 10/4 28%
Tue 10/6 4%
Wed 10/7 4%
Odds over time
Arrive at HOU more than 15 minutes late?
3%
chance · ±0 pts
−10 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
3%
Leave 15+ late
4%
Arrive 1h+ late
<1%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
2.9d
2d
1d
12h
6h
Departs
Lands
Arrive at HOU more than 15 minutes late?
Calm-weather odds: 3% · changed −10 pts in 24h
−10 pts
3%
Yes 3%
No 97%
Leave DEN more than 15 minutes late?
Calm-weather odds: 4% · changed −1 pt in 24h
−1 pt
4%
Yes 4%
No 96%
Arrive at HOU more than an hour late?
Calm-weather odds: <1% · changed −2 pts in 24h
−2 pts
<1%
Yes <1%
No 99%
Cancelled?
Calm-weather odds: <1% · changed −1 pt in 24h
−1 pt
<1%
Yes <1%
No 99%
How late will it get to HOU?
On time or early
96%
15–30 min late
1%
30 min–1 hour late
1%
1–2 hours late
<1%
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
↑
DEN is busy at that time
↑
This flight has been late 25% of the time recently
↓
Early flights usually leave on time
↓
Mostly benign weather forecast at DEN
Weather at each end
DEN (origin)
Gusts 20 kt Ceiling 8,000 ft Visibility 10+ mi Precip 0.03 in
HOU (destination)
Gusts 22 kt Ceiling 5,000 ft 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.