It's actually a bit more complex.
There are multiple ground tower types. The METARS and TAFS are broadcast only for areas around the towers in different ways:
Surface stations broadcast:
Winds and temperature aloft within a range of 500 NM
Regional NEXRAD within a range of 150 NM
METARs, TAFs, SIGMET, and NOTAM within a range of 100 NM
Low altitude stations broadcast:
Winds and temperature aloft within a range of 500 NM
METARs, TAFs, AIRMET, SIGMET, PIREP, and SUA within a range of 250 NM
Regional NEXRAD within a range of 150 NM (no CONUS NEXRAD is broadcast from low altitude stations)
NOTAM within a range of 100 NM
Medium altitude stations broadcast:
Entire CONUS NEXRAD
Winds and temperature aloft within a range of 750 NM
METARs, TAFs, AIRMET, SIGMET, PIREP, and SUA within a range of 375 NM
Regional NEXRAD within a range of 200 NM
NOTAM within a range of 100 NM
High altitude stations broadcast:
Entire CONUS NEXRAD
Winds and temperature aloft and all 158 CONUS Class B/C airport METAR/TAF within a range of 1000 NM
AIRMET, SIGMET, PIREP, and SUA within a range of 500 NM
Regional NEXRAD within a range of 250 NM
NOTAM within a range of 100 NM
The thing to know is that once you are up in cruise, you almost always have a Medium and High altitude station in view, so you get Class B/C for 1000NM, and all METAR/TAF for 375NM.