Fog

[Nights King]

Where i live we suffer from low cloud fog alot of the year but radiation fog is quite a rare thing where i live and just wondered why?

I understand how radiation fog forms however why does it not form on the plateux of the hills so much? I realise that if on side of hill it will sink but why on the flat? Is it something to do with cooler temps higher up or is it just breezier higher up so it gets blown towards the edge of hills so it sinks into the lower areas?

I drive into bristol every day and see fog on my way in often but normally below 150-200m just ocasionaly does it creep up to the higher ground around november and december.