Maybe cool for half an hour in the shade (6)
I believe the answer is:
colour
'shade' is the definition.
(I've seen this before)
'maybe cool for half an hour' is the wordplay.
'maybe' is an anagram indicator.
'for' means one lot of letters go next to another.
'half an' indicates taking half.
'hour' with half the letters taken is 'ur'.
'cool' is an anagram of 'colo'.
'colo'+'ur'='COLOUR'
'in the' is the link.
(Other definitions for colour that I've seen before include "black?" , "Distort; blush; hue" , "See 10" , "'Tinge, hue (6)'" , "Go red" .)