Apparatus

Try JFK, AAL1290, BAW, or N225AN.

flight_takeoff Flight

UAL521

Operated by UAL

Live map

Live map filtered to UAL521. Shown when the flight is currently airborne.

Route airports View route page →

Departure

IAH KIAH VFR

George Bush Intercontinental Airport

Houston, US

Local time
21:59 CDT
Timezone
America/Chicago
Type
Large Airport
Elevation
97 ft
Coordinates
29.9844, -95.3414

cloud Weather

Wind
160° / 3 kt
Visibility
10 SM
Ceiling
SCT 19,000 ft, BKN 25,000 ft
Temp / Dew
25°C / 24°C
Altimeter
29.97 inHg

Obs: 2026-08-29T01:53:00.000Z

Raw METAR / TAF 
METAR KIAH 290153Z 16003KT 10SM SCT190 BKN250 25/24 A2997 RMK AO2 SLP150 T02500244

TAF KIAH 290246Z 2903/3006 14005KT P6SM SCT040 FM290600 VRB05KT P6SM FEW030 FM291800 14007KT P6SM SCT250 FM300300 18005KT P6SM SCT250

flight Live Traffic

flight_takeoff 174 Departures
flight_land 158 Arrivals

Arrival

BOS KBOS VFR

Boston Logan International Airport

Boston, US

Local time
22:59 EDT
Timezone
America/New_York
Type
Large Airport
Elevation
20 ft
Coordinates
42.3620, -71.0079

cloud Weather

Wind
290° / 9 kt
Visibility
10 SM
Ceiling
FEW 25,000 ft
Temp / Dew
26°C / 15°C
Altimeter
29.99 inHg

Obs: 2026-08-29T01:54:00.000Z

Raw METAR / TAF 
METAR KBOS 290154Z 29009KT 10SM FEW250 26/15 A2999 RMK AO2 SLP155 T02560150 $

TAF KBOS 282320Z 2900/3006 28008KT P6SM FEW050 FM290400 34010G18KT P6SM FEW050 FM291300 02006KT P6SM SKC FM291600 12010KT P6SM SKC FM300000 19006KT P6SM SKC

flight Live Traffic

flight_takeoff 244 Departures
flight_land 248 Arrivals

Recent history last 30

DateAircraftRouteTakeoffLandingDurationDep ΔArr Δ
2026-07-25 AB48E8 JFK → SFO Jul 25, 19:40 UTCJul 25, 23:15 UTC3h 35m - -
2026-07-25 AB48E8 JFK → SFO Jul 25, 19:47 UTCJul 25, 23:14 UTC3h 27m +17m +19m
2026-07-25 A44963 JFK → SFO Jul 25, 00:10 UTCJul 25, 03:25 UTC3h 15m - -
2026-07-24 A44963 JFK → SFO Jul 24, 01:00 UTCJul 24, 04:20 UTC3h 20m - -
2026-07-24 A44963 JFK → SFO Jul 24, 00:36 UTCJul 24, 04:15 UTC3h 39m +81m -29m
2026-07-23 A44983 JFK → SFO Jul 23, 00:05 UTCJul 23, 03:20 UTC3h 15m - -
2026-07-22 A44983 JFK → SFO Jul 22, 23:46 UTCJul 23, 03:23 UTC3h 37m +31m -17m
2026-07-22 A2BB89 JFK → SFO Jul 22, 00:15 UTCJul 22, 03:30 UTC3h 15m - -
2026-07-20 A12AE4 JFK → SFO Jul 20, 23:45 UTCJul 21, 03:10 UTC3h 25m - -
2026-07-19 A448D5 JFK → SFO Jul 19, 23:35 UTCJul 20, 03:20 UTC3h 45m - -
2026-07-18 AB2C8E JFK → SFO Jul 18, 21:45 UTCJul 19, 01:35 UTC3h 50m - -
2026-07-17 A12A7C JFK → SFO Jul 17, 23:30 UTCJul 18, 02:55 UTC3h 26m - -
2026-07-17 A12A7C - Jul 17, 00:04 UTCJul 17, 03:14 UTC3h 10m - -
2026-07-16 A448F8 - Jul 16, 00:30 UTCJul 16, 03:45 UTC3h 15m - -
2026-07-15 A75FDF - Jul 15, 00:00 UTCJul 15, 03:35 UTC3h 35m - -
2026-07-14 A12B2D - Jul 14, 02:30 UTCJul 14, 05:55 UTC3h 25m - -
2026-07-13 A448F2 - Jul 13, 00:45 UTCJul 13, 03:20 UTC2h 35m - -
2026-07-12 A448F2 - Jul 12, 23:50 UTCJul 13, 00:40 UTC50m - -
2026-07-11 AB2520 - Jul 11, 19:50 UTCJul 11, 23:35 UTC3h 45m - -
2026-07-10 AA7F2A - Jul 10, 23:35 UTCJul 11, 02:45 UTC3h 10m - -
2026-07-09 A12F09 - Jul 9, 23:40 UTCJul 10, 03:10 UTC3h 30m - -
2026-07-08 A12B2F - Jul 8, 23:35 UTCJul 9, 02:55 UTC3h 20m - -
2026-07-08 A2B7F5 - Jul 8, 02:50 UTCJul 8, 06:05 UTC3h 15m - -
2026-07-07 A4493D - Jul 7, 00:30 UTCJul 7, 04:00 UTC3h 30m - -
2026-07-06 A449A2 - Jul 6, 00:10 UTCJul 6, 03:30 UTC3h 20m - -
2026-07-04 A612A6 - Jul 4, 19:40 UTCJul 4, 23:30 UTC3h 50m - -
2026-07-04 A12F75 - Jul 4, 02:40 UTCJul 4, 03:30 UTC50m - -
2026-07-03 A12EE0 - Jul 3, 00:00 UTCJul 3, 03:20 UTC3h 20m - -
2026-07-02 A2BB83 - Jul 2, 01:10 UTCJul 2, 04:35 UTC3h 25m - -
2026-06-30 AA7F09 - Jun 30, 23:50 UTCJul 1, 03:20 UTC3h 30m - -

Performance history

Flights tracked
152 showing last 30
Avg arrival delay
-9m
On-time arrival
67% 67% on time
Aircraft used
24

Monthly activity 4 months

Month Flights tracked
July 2026 29
June 2026 29
May 2026 45
April 2026 49

UAL521 frequently asked

Where does flight UAL521 fly?
UAL521 (UAL) flies from IAH to BOS. View the full route page.
How long is flight UAL521?
Based on observed flights, UAL521 takes on average 3h 15m from takeoff to landing.
How often does UAL521 fly?
UAL521 has been observed flying several times a week in our tracking data. We've recorded 152 flights under this callsign.
Is flight UAL521 usually on time?
Across recent flights, UAL521 arrives 9 minutes early on average. 67% of flights arrive within 15 minutes of schedule.
What aircraft operates flight UAL521?
UAL521 has been operated by 24 different aircraft in our records. Tail numbers are listed in the recent history below.
Can I track UAL521 live?
Yes. When UAL521 is currently airborne, the live tracker map above shows its real-time position from ADS-B broadcasts. If the map is empty, the flight is not currently in the air.