Is UA4639 delayed?
No — UA4639 landed in San Francisco 35 min early, at 08:43 on Sep 29 (as of Sep 29, 16:14 UTC).
Often late: arrived more than 15 min after schedule on 13 of the last 26 flights.
35 min early
Official source · Updated
Departure
Boise
BOI
Scheduled
Not available
Arrival
San Francisco
SFO
Actual
Scheduled 09:18
Sep 29
Times shown in airport local time
Service date: · Scheduled arrival date; departure time unavailable (America/Los_Angeles)
Market settled: On time.
Flight details
Departure · UTC
- Scheduled
- Not available
- Estimated
- Not available
- Actual
- Not available
Arrival · UTC
- Scheduled
- Estimated
- Actual
Market prices express trading expectations about a contract’s stated threshold. They do not confirm airline status. The linked market shows its terms and activity.
Also sold as AC3997, AC4229, AC4378, NH7335, NZ9392
Recent arrivals
Dates below are arrival dates in the destination airport’s time zone. The detailed history uses service dates.
- 35 min early
Boise → San Francisco
- 25 min late
Boise → San Francisco
- 47 min late
Boise → San Francisco
- On schedule (2 min behind)
Boise → San Francisco
- 48 min late
Boise → San Francisco
Is UA4639 usually late?
Observation window: Aug 30, 2026 – Sep 29, 2026
On time means arriving no more than 15 minutes after the scheduled time; late means more than 15 minutes after. Cancelled and diverted flights are counted apart from arrivals. Results compare scheduled and actual arrival times. Cancelled or diverted flights are excluded. Some flights may be missing from the history.
At the airports today
San Francisco (SFO) departures
- Left more than 15 min late
- 94 of 253
- Cancelled today
- 1
Related flights
Flight history and details
| Service date | Departure | Arrival | Actual | Arrival delay (minutes) |
|---|---|---|---|---|
| Sep 29, 2026Arrived | Boise | San Francisco | -35 | |
| Sep 28, 2026Arrived | Boise | San Francisco | 25 | |
| Sep 27, 2026Arrived | Boise | San Francisco | 47 | |
| Sep 26, 2026Arrived | Boise | San Francisco | 2 | |
| Sep 25, 2026Arrived | Boise | San Francisco | 48 | |
| Sep 24, 2026Arrived | Boise | San Francisco | -12 | |
| Sep 23, 2026Arrived | Boise | San Francisco | 16 | |
| Sep 22, 2026Arrived | Boise | San Francisco | 25 | |
| Sep 21, 2026Arrived | Boise | San Francisco | 13 | |
| Sep 20, 2026Arrived | Boise | San Francisco | 43 | |
| Sep 19, 2026Arrived | Boise | San Francisco | 43 | |
| Sep 18, 2026Arrived | Boise | San Francisco | 62 | |
| Sep 17, 2026Arrived | Boise | San Francisco | 30 | |
| Sep 16, 2026Arrived | Boise | San Francisco | 20 | |
| Sep 15, 2026Arrived | Boise | San Francisco | -14 | |
| Sep 14, 2026Arrived | Boise | San Francisco | -19 | |
| Sep 13, 2026Arrived | Boise | San Francisco | -15 | |
| Sep 12, 2026Arrived | Boise | San Francisco | -13 | |
| Sep 11, 2026Arrived | Boise | San Francisco | 44 | |
| Sep 10, 2026Arrived | Boise | San Francisco | -18 | |
| Sep 9, 2026Arrived | Boise | San Francisco | 13 | |
| Sep 8, 2026Arrived | Boise | San Francisco | -18 | |
| Sep 7, 2026Arrived | Boise | San Francisco | 17 | |
| Sep 6, 2026Arrived | Boise | San Francisco | 6 | |
| Sep 5, 2026Arrived | Boise | San Francisco | 50 | |
| Sep 4, 2026Arrived | Boise | San Francisco | -10 |
Email me if UA4639 runs late
We email you if your next UA4639 flight in the coming day is more than 15 minutes late, cancelled or diverted. Alerts last 30 days. No account needed.