Complex sentence: Outside of winter, temperatures in central Khyber Pakhtunkhwa are not so hot as in Chitral, but significantly higher humidity when the monsoon is active means that heat discomfort can be greater.
Split into simpler sentences: Outside of winter, temperatures in central Khyber Pakhtunkhwa are not so hot as in Chitral. Significantly higher humidity when the monsoon is active means that heat discomfort can be greater.