Not the weather to be out, since there's little sunshine about (5)
I believe the answer is:
rainy
'not the weather to be out since' is the definition.
I can't judge whether this definition defines the answer.
'there's little sunshine about' is the wordplay.
'there's' becomes 'in' (I can't justify this - if you can you should give a lot more credence to this answer).
'little' means to remove the last letter (the word is not quite complete).
'sunshine' becomes 'rays'.
'about' indicates putting letters inside.
'rays' with its final letter taken away is 'ray'.
'in' going inside 'ray' is 'RAINY'.
Can you help me to learn more?
(Other definitions for rainy that I've seen before include "With water falling outside" , "Drizzly" , "Save your money for this damp day" , "Save your money for a . . . . . day - to buy an umbrella?" , "Pluvial" .)