Schedule: a typical Tuesday (the flights of Jul 28, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
FRONTIER · FLIGHT F9 4578
SCHEDULED · TYPICAL SCHEDULE
Tuesday, September 29 Today
F9 4578 · SAN → PHX
departs 4:12 PM PT · arrives 5:41 PM MT
Forecast issued Tue 3:00 PM ET · 4h before departure
Watch this flight
Other days
Today
Wed 9/30 37%
Thu 10/1 38%
Fri 10/2 40%
Sat 10/3 32%
Sun 10/4 42%
Mon 10/5 44%
Odds over time
Arrive at PHX more than 15 minutes late?
37%
chance · ±1 pts
−8 pts · 24h
HOW SURE WE ARE
High. The odds now come mostly from live FAA and airport data.
Arrive 15+ late
37%
Leave 15+ late
44%
Arrive 1h+ late
21%
Cancelled
2%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
20%
40%
60%
80%
2.8d
2d
1d
12h
6h
Now
Departs
Lands
Arrive at PHX more than 15 minutes late?
Calm-weather odds: 37% · changed −8 pts in 24h
−8 pts
37%
Yes 37%
No 63%
Leave SAN more than 15 minutes late?
Calm-weather odds: 42% · changed +13 pts in 24h
+13 pts
44%
Yes 44%
No 56%
Arrive at PHX more than an hour late?
Calm-weather odds: 17% · changed +9 pts in 24h
+9 pts
21%
Yes 21%
No 79%
Cancelled?
Calm-weather odds: 1% · changed +0 pts in 24h
+0 pts
2%
Yes 2%
No 98%
How late will it get to PHX?
On time or early
62%
15–30 min late
12%
30 min–1 hour late
4%
1–2 hours late
16%
Over 2 hours late
4%
Cancelled
2%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
F9's recent on-time record
↑
4pm departures from SAN are often late
↑
Arrivals into PHX at that hour are often late
↓
Mostly benign weather forecast at SAN
↓
Tuesdays in September are usually quieter than average
Weather at each end
SAN (origin)
Gusts 9 kt Ceiling 2,300 ft Visibility 10+ mi Precip none
PHX (destination)
Gusts 20 kt Ceiling 1,800 ft Visibility 1.75 mi Precip 0.67 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.