Schedule: a typical Wednesday (the flights of Jul 29, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
ALLEGIANT · FLIGHT G4 581
SCHEDULED · TYPICAL SCHEDULE
Wednesday, September 30 Yesterday
G4 581 · GRR → SFB
departs 2:55 PM ET · arrives 5:29 PM ET
Forecast issued Wed 10:00 PM ET · 7h after departure
Watch this flight
Other days
Wed 9/30
Sat 10/3 8%
Wed 10/7 18%
Odds over time
Arrive at SFB more than 15 minutes late?
30%
chance · ±0 pts
+10 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
30%
Leave 15+ late
35%
Arrive 1h+ late
13%
Cancelled
<1%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
2.8d
2d
1d
12h
6h
Departs
Lands
Arrive at SFB more than 15 minutes late?
Calm-weather odds: 30% · changed +10 pts in 24h
+10 pts
30%
Yes 30%
No 70%
Leave GRR more than 15 minutes late?
Calm-weather odds: 35% · changed +11 pts in 24h
+11 pts
35%
Yes 35%
No 65%
Arrive at SFB more than an hour late?
Calm-weather odds: 12% · changed +4 pts in 24h
+4 pts
13%
Yes 13%
No 87%
Cancelled?
Calm-weather odds: <1% · changed +0 pts in 24h
+0 pts
<1%
Yes <1%
No 99%
How late will it get to SFB?
On time or early
69%
15–30 min late
5%
30 min–1 hour late
12%
1–2 hours late
7%
Over 2 hours late
6%
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 1.25 mi, 0.4 in of rain forecast at GRR that day
↑
Mostly benign weather forecast at SFB
↑
Arrivals into SFB at that hour are often late
↓
Wednesdays in September are usually quieter than average
↓
GRR usually runs smoothly
Weather at each end
GRR (origin)
Gusts 11 kt Ceiling 600 ft Visibility 1.25 mi Precip 0.35 in
SFB (destination)
Gusts 8 kt Ceiling 7,500 ft Visibility 10+ mi Precip 0.21 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.