English, cold and wet outside, take flight (6)
I believe the answer is:
decamp
'take flight' is the definition.
(decamping is a kind of taking flight)
'english cold and wet outside' is the wordplay.
'english' becomes 'e' (abbreviation).
'cold' becomes 'c' (eg on taps).
'and' is a charade indicator (letters next to each other).
'wet' becomes 'damp' ('damp' can be similar in meaning to 'wet').
'outside' indicates putting letters inside.
'e'+'c'='ec'
'ec' going within 'damp' is 'DECAMP'.
(Other definitions for decamp that I've seen before include "escape" , "Bolt" , "Go away suddenly or secretly - leaving tent?" , "Make off secretly" , "Depart suddenly or secretly" .)