Schedule: a typical summer Thursday (the flights of Jul 30, 2026), re-dated. Real flights replace these once airlines file their FAA flight plans, usually about a day ahead.
FRONTIER · FLIGHT F9 3999
SCHEDULED · TYPICAL SCHEDULE
Thursday, October 1 Yesterday
F9 3999 · DFW → SFO
departs 8:59 PM CT · arrives 10:59 PM PT
Forecast issued Thu 10:00 PM ET · 0h before departure
Watch this flight
Other days
Thu 10/1
Today 46%
Sat 10/3 44%
Sun 10/4 45%
Mon 10/5 36%
Tue 10/6 25%
Wed 10/7 31%
Odds over time
Arrive at SFO more than 15 minutes late?
56%
chance · ±2 pts
−8 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
56%
Leave 15+ late
53%
Arrive 1h+ late
25%
Cancelled
7%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
25%
50%
75%
100%
2.8d
2d
1d
12h
6h
Departs
Lands
Arrive at SFO more than 15 minutes late?
Calm-weather odds: 56% · changed −8 pts in 24h
−8 pts
56%
Yes 56%
No 44%
Leave DFW more than 15 minutes late?
Calm-weather odds: 54% · changed −12 pts in 24h
−12 pts
53%
Yes 53%
No 47%
Arrive at SFO more than an hour late?
Calm-weather odds: 23% · changed −14 pts in 24h
−14 pts
25%
Yes 25%
No 75%
Cancelled?
Calm-weather odds: 6% · changed −9 pts in 24h
−9 pts
7%
Yes 7%
No 93%
How late will it get to SFO?
On time or early
41%
15–30 min late
<1%
30 min–1 hour late
29%
1–2 hours late
11%
Over 2 hours late
12%
Cancelled
7%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.
What’s moving the odds
↑
Cloud base down to 300 ft, visibility down to 1 mi, 4.1 in of rain, thunderstorms forecast at DFW that day
↑
8pm departures from DFW are often late
↑
This flight has been late 42% of the time recently
↓
Cloud base down to 500 ft forecast at SFO that day
↓
Thursdays in October are usually quieter than average
Weather at each end
DFW (origin)
Gusts 24 kt Ceiling 300 ft Visibility 1 mi Precip 4.07 in
SFO (destination)
Gusts 24 kt Ceiling 500 ft Visibility 6 mi Precip none
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.