Schedule: a typical summer Tuesday (the flights of Jul 28, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
REPUBLIC · FLIGHT YX 4678
SCHEDULED · TYPICAL SCHEDULE
Tuesday, September 29
YX 4678 · STL → BOS
departs 7:51 PM CT · arrives 11:37 PM ET
Forecast issued Tue 10:00 PM ET · 1h after departure
Watch this flight
Other days
Tue 9/29
Today 33%
Sat 10/3 19%
Sun 10/4 34%
Mon 10/5 30%
Tue 10/6 20%
Wed 10/7 28%
Odds over time
Arrive at BOS more than 15 minutes late?
46%
chance · ±1 pts
+16 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
46%
Leave 15+ late
33%
Arrive 1h+ late
20%
Cancelled
1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
2.8d
2d
1d
12h
6h
Departs
Now
Lands
Arrive at BOS more than 15 minutes late?
Calm-weather odds: 41% · changed +16 pts in 24h
+16 pts
46%
Yes 46%
No 54%
Leave STL more than 15 minutes late?
Calm-weather odds: 32% · changed +5 pts in 24h
+5 pts
33%
Yes 33%
No 67%
Arrive at BOS more than an hour late?
Calm-weather odds: 15% · changed +9 pts in 24h
+9 pts
20%
Yes 20%
No 80%
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
54%
15–30 min late
4%
30 min–1 hour late
21%
1–2 hours late
16%
Over 2 hours late
4%
Cancelled
1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Cloud base down to 600 ft, visibility down to 1.5 mi forecast at BOS that day
↑
Arrivals into BOS at that hour are often late
↑
BOS is prone to delays
↓
Mostly benign weather forecast at STL
↓
Tuesdays in September are usually quieter than average
Weather at each end
STL (origin)
Gusts 9 kt Ceiling none (clear) Visibility 10+ mi Precip none
BOS (destination)
Gusts 11 kt Ceiling 600 ft Visibility 1.5 mi Precip 0.03 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.