Street includes area that’s sheltered – from this, perhaps (5)
'this perhaps' is the definition.
The definition suggests a singular noun which matches the answer.
'street includes area that's sheltered' is the wordplay.
'street' becomes 'st'.
'includes' is an insertion indicator.
'area that's sheltered' becomes 'lee' (the side sheltered from wind).
'st' enclosing 'lee' is 'SLEET'.
'from' is the link.
(Other definitions for sleet that I've seen before include "In foul weather", "Rain mixed with snow or hail", "Icy rain", "Precipitate evolution", "Partly frozen rain".)