Look round everywhere, initially for a sign of summer (3)
I believe the answer is:
leo
'a sign of summer' is the definition.
(I've seen this before)
'look round everywhere initially' is the wordplay.
'look' becomes 'lo' ().
'round' is an insertion indicator.
'initially' says to take the initial letters.
The initial letter of 'everywhere' is 'e'.
'lo' placed around 'e' is 'LEO'.
'for' is the link.
(Other definitions for leo that I've seen before include "Zodiacal lion" , "Man" , "Name taken by 13 popes, the last dying in 1903 aged 93" , "sign of summer" , "Pope" .)