Showery at home, interrupting bit of sunshine (5)
I believe the answer is:
rainy
'showery' is the definition.
(I know that showery can be written as rainy)
'home interrupting bit of sunshine' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'interrupting' means one lot of letters goes inside another.
'bit of sunshine' becomes 'ray' (a ray of light).
'in' placed into 'ray' is 'RAINY'.
'at' is the link.
(Other definitions for rainy that I've seen before include "(Of weather) wet" , "The day one saves for" , "With water falling outside" , "Drizzly" , "Save your money for a . . . . . day - to buy an umbrella?" .)