Great heat and light rain making month squally at first (6)
I believe the answer is:
sizzle
'great heat' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for sizzle that I've seen before include "Sound of frying sausages" , "Make a hissing sound while frying" , "Frying hiss" , "Fizz in the pan" , "Fry" .)