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 3907
SCHEDULED · TYPICAL SCHEDULE
Sunday, October 4
WN 3907 · STL → DCA
departs 3:45 PM CT · arrives 6:45 PM ET
Forecast issued Fri 7:00 PM ET · 46h before departure
Watch this flight
Other days
Today 30%
Sat 10/3 25%
Sun 10/4
Mon 10/5 24%
Odds over time
Arrive at DCA more than 15 minutes late?
41%
chance · ±0 pts
+4 pts · 24h
HOW SURE WE ARE
Moderate. The odds now blend history with early weather forecasts.
Arrive 15+ late
41%
Leave 15+ late
35%
Arrive 1h+ late
11%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
5.8d
Now
1d
12h
6h
Departs
Lands
Arrive at DCA more than 15 minutes late?
Calm-weather odds: 22% · changed +4 pts in 24h
+4 pts
41%
Yes 41%
No 59%
Leave STL more than 15 minutes late?
Calm-weather odds: 24% · changed +1 pt in 24h
+1 pt
35%
Yes 35%
No 65%
Arrive at DCA more than an hour late?
Calm-weather odds: 5% · changed +2 pts in 24h
+2 pts
11%
Yes 11%
No 89%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to DCA?
On time or early
58%
15–30 min late
15%
30 min–1 hour late
15%
1–2 hours late
8%
Over 2 hours late
3%
Cancelled
<1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Cloud base down to 500 ft, 0.5 in of rain forecast at DCA that day
↑
Arrivals into DCA at that hour are often late
↑
Later flights pick up delays from earlier in the day
↓
Mostly benign weather forecast at STL
↓
Sundays in October are usually quieter than average
Weather at each end
STL (origin)
Gusts 10 kt Ceiling none (clear) Visibility 8 mi Precip none
DCA (destination)
Gusts 9 kt Ceiling 700 ft Visibility 1 mi Precip 0.46 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.