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 1221
SCHEDULED · TYPICAL SCHEDULE
Sunday, October 4 Today
WN 1221 · BWI → BOS
departs 10:25 AM ET · arrives 11:55 AM ET
Forecast issued Sun 4:00 AM ET · 6h before departure
Watch this flight
Odds over time
Arrive at BOS more than 15 minutes late?
22%
chance · ±0 pts
+12 pts · 24h
HOW SURE WE ARE
Good. The odds now lean mostly on firmed-up weather forecasts.
Arrive 15+ late
22%
Leave 15+ late
29%
Arrive 1h+ late
3%
Cancelled
<1%
MOSTLY HISTORY
WEATHER FORECASTS
LIVE
IN THE AIR
0%
10%
20%
30%
40%
5.5d
2d
1d
12h
Now
Departs
Lands
Arrive at BOS more than 15 minutes late?
Calm-weather odds: 11% · changed +12 pts in 24h
+12 pts
22%
Yes 22%
No 78%
Leave BWI more than 15 minutes late?
Calm-weather odds: 14% · changed +13 pts in 24h
+13 pts
29%
Yes 29%
No 71%
Arrive at BOS more than an hour late?
Calm-weather odds: 2% · changed +0 pts in 24h
+0 pts
3%
Yes 3%
No 97%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to BOS?
On time or early
78%
15–30 min late
11%
30 min–1 hour late
8%
1–2 hours late
2%
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
↑
This flight has been late 22% of the time recently
↑
Cloud base down to 200 ft forecast at BWI that day
↑
BWI is busy at that time
↓
BOS usually runs smoothly
↓
Early flights usually leave on time
Weather at each end
BWI (origin)
Gusts 13 kt Ceiling 300 ft Visibility 3 mi Precip 0.16 in
BOS (destination)
Gusts 15 kt Ceiling 800 ft Visibility 6 mi Precip 0.13 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.