The two most common causes of interference are transmitters and electrical equipment.
How do I stop interference on my FM radio?
For FM, in some instances relocating your aerial to a new location, through placing a barrier (eg, roof or house) between your aerial and the interfering signal, may lessen or remove the effect of the interference. A change of aerial height may also reduce the effect.
Is FM prone to interference?
Anything using electric power can cause interference. On AM and FM radios, the interference is characteristically heard as a buzzing noise, whine or hiss — affecting mains and battery operated radios. AM reception is more prone to interference than FM reception.