Schedule: a typical Thursday (the flights of Jul 30, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
SOUTHWEST · FLIGHT WN 621
SCHEDULED · TYPICAL SCHEDULE
Thursday, October 1
WN 621 · SJC → BWI
departs 9:40 PM PT · arrives 5:45 AM ET
Forecast issued Wed 12:00 AM ET · 49h before departure
Watch this flight
Other days
Today 15%
Thu 10/1
Fri 10/2 24%
Sat 10/3 14%
Sun 10/4 21%
Mon 10/5 18%
Tue 10/6 13%
Odds over time
Arrive at BWI more than 15 minutes late?
22%
chance · ±2 pts
– · 24h
HOW SURE WE ARE
Moderate. The odds now blend history with early weather forecasts.
Arrive 15+ late
22%
Leave 15+ late
22%
Arrive 1h+ late
5%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
2.7d
Now
1d
12h
6h
Departs
Lands
Arrive at BWI more than 15 minutes late?
Calm-weather odds: 19% · changed – in 24h
–
22%
Yes 22%
No 78%
Leave SJC more than 15 minutes late?
Calm-weather odds: 21% · changed – in 24h
–
22%
Yes 22%
No 78%
Arrive at BWI more than an hour late?
Calm-weather odds: 4% · changed – in 24h
–
5%
Yes 5%
No 95%
Cancelled?
Calm-weather odds: <1% · changed – in 24h
–
<1%
Yes <1%
No 100%
How late will it get to BWI?
On time or early
77%
15–30 min late
12%
30 min–1 hour late
5%
1–2 hours late
4%
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
↑
Later flights pick up delays from earlier in the day
↑
WN's recent on-time record
↑
9pm departures from SJC are often late
↓
Cloud base down to 800 ft forecast at SJC that day
↓
Mostly benign weather forecast at BWI
Weather at each end
SJC (origin)
Gusts 10 kt Ceiling 800 ft Visibility 4 mi Precip none
BWI (destination)
Gusts 10 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.