Schedule: a typical Saturday (the flights of Jul 25, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4578
SCHEDULED · TYPICAL SCHEDULE
Saturday, October 3
WN 4578 · BWI → TPA
departs 8:45 PM ET · arrives 11:20 PM ET
Forecast issued Thu 8:00 PM ET · 49h before departure
Watch this flight
Other days
Today 22%
Fri 10/2 35%
Sat 10/3
Mon 10/5 12%
Tue 10/6 12%
Wed 10/7 14%
Odds over time
Arrive at TPA more than 15 minutes late?
30%
chance · ±6 pts
– · 24h
HOW SURE WE ARE
Moderate. The odds now blend history with early weather forecasts.
Arrive 15+ late
30%
Leave 15+ late
42%
Arrive 1h+ late
13%
Cancelled
1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
4.9d
Now
1d
12h
6h
Departs
Lands
Arrive at TPA more than 15 minutes late?
Calm-weather odds: 13% · changed – in 24h
–
30%
Yes 30%
No 70%
Leave BWI more than 15 minutes late?
Calm-weather odds: 20% · changed – in 24h
–
42%
Yes 42%
No 58%
Arrive at TPA more than an hour late?
Calm-weather odds: 5% · changed – in 24h
–
13%
Yes 13%
No 87%
Cancelled?
Calm-weather odds: <1% · changed – in 24h
–
1%
Yes 1%
No 99%
How late will it get to TPA?
On time or early
69%
15–30 min late
13%
30 min–1 hour late
4%
1–2 hours late
10%
Over 2 hours late
2%
Cancelled
1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Mostly benign weather forecast at BWI
↑
Later flights pick up delays from earlier in the day
↑
0.3 in of rain forecast at TPA that day
↓
Other factors
↓
WN's recent on-time record
Weather at each end
BWI (origin)
Gusts 15 kt Ceiling 3,800 ft Visibility 10+ mi Precip 0.20 in
TPA (destination)
Gusts 12 kt Ceiling 5,000 ft Visibility 10+ mi Precip 0.30 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.