Schedule: a typical summer Sunday (the flights of Jul 26, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
SOUTHWEST · FLIGHT WN 4509
SCHEDULED · TYPICAL SCHEDULE
Sunday, October 4 Tomorrow
WN 4509 · BWI → SAN
departs 6:15 AM ET · arrives 8:30 AM PT
Forecast issued Sat 3:00 PM ET · 15h before departure
Watch this flight
Odds over time
Arrive at SAN more than 15 minutes late?
15%
chance · ±1 pts
+3 pts · 24h
HOW SURE WE ARE
Good. The odds now lean mostly on firmed-up weather forecasts.
Arrive 15+ late
15%
Leave 15+ late
8%
Arrive 1h+ late
2%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
5%
10%
15%
20%
5.3d
2d
1d
Now
6h
Departs
Lands
Arrive at SAN more than 15 minutes late?
Calm-weather odds: 13% · changed +3 pts in 24h
+3 pts
15%
Yes 15%
No 85%
Leave BWI more than 15 minutes late?
Calm-weather odds: 6% · changed +0 pts in 24h
+0 pts
8%
Yes 8%
No 92%
Arrive at SAN more than an hour late?
Calm-weather odds: 1% · changed +0 pts in 24h
+0 pts
2%
Yes 2%
No 98%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to SAN?
On time or early
84%
15–30 min late
11%
30 min–1 hour late
3%
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
↑
SAN is prone to delays
↑
BWI is prone to delays
↑
Cloud base down to 200 ft, visibility down to 0.5 mi forecast at BWI that day
↓
Early flights usually leave on time
↓
Mostly benign weather forecast at SAN
Weather at each end
BWI (origin)
Gusts 11 kt Ceiling 200 ft Visibility 0.5 mi Precip 0.13 in
SAN (destination)
Gusts 14 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.