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.
FRONTIER · FLIGHT F9 4278
SCHEDULED · TYPICAL SCHEDULE
Tuesday, September 29
F9 4278 · LAS → IAD
departs 12:46 AM PT · arrives 8:20 AM ET
Forecast issued Tue 10:00 PM ET · 18h after departure
Watch this flight
Other days
Tue 9/29
Today 25%
Sat 10/3 23%
Sun 10/4 28%
Mon 10/5 27%
Odds over time
Arrive at IAD more than 15 minutes late?
33%
chance · ±0 pts
+8 pts · 24h
HOW SURE WE ARE
Very high. The odds now come almost entirely from live conditions.
Arrive 15+ late
33%
Leave 15+ late
42%
Arrive 1h+ late
13%
Cancelled
2%
WEATHER FORECASTS
LIVE
IN THE AIR
0%
15%
30%
45%
60%
2.7d
2d
1d
12h
6h
Departs
Lands
Arrive at IAD more than 15 minutes late?
Calm-weather odds: 35% · changed +8 pts in 24h
+8 pts
33%
Yes 33%
No 67%
Leave LAS more than 15 minutes late?
Calm-weather odds: 43% · changed +14 pts in 24h
+14 pts
42%
Yes 42%
No 58%
Arrive at IAD more than an hour late?
Calm-weather odds: 13% · changed +5 pts in 24h
+5 pts
13%
Yes 13%
No 87%
Cancelled?
Calm-weather odds: 2% · changed +1 pt in 24h
+1 pt
2%
Yes 2%
No 98%
How late will it get to IAD?
On time or early
66%
15–30 min late
7%
30 min–1 hour late
13%
1–2 hours late
9%
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
↑
Gusts to 27 kt forecast at LAS that day
↑
This flight has been late 26% of the time recently
↓
Early flights usually leave on time
↓
Tuesdays in September are usually quieter than average
Weather at each end
LAS (origin)
Gusts 27 kt Ceiling 4,700 ft Visibility 7 mi Precip 0.08 in
IAD (destination)
Gusts 9 kt Ceiling 4,200 ft Visibility 8.8 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.