Calm end to summer with flutes playing (7)
I believe the answer is:
restful
'calm' is the definition.
(restful means calm or quiet)
'end to summer with flutes playing' is the wordplay.
'end to' suggests the final letters.
'with' means one lot of letters go next to another.
'playing' is an anagram indicator.
The final letter of 'summer' is 'r'.
'flutes' is an anagram of 'estful'.
'r'+'estful'='RESTFUL'
(Other definitions for restful that I've seen before include "Quiet, soothing" , "Calm" , "Still - calming" , "Sedative" , "Soothing is required" .)