Do you notice that sunny and very hot weather usually precedes the approach of typhoons? 

Near the center of the typhoon, there is intense spiral rising air. When the rising air reaches the top of the troposphere, they could no longer rise but spread sideways and subside in the typhoons neighboring areas.  

The subsiding air often brings hot water (while rising air tends to cool with height). First, subsiding air brings less cloud cover and intense sunshine, and abundant sunshine causes temperatures over inland areas to rise sharply. In addition, the subsiding air is like a pot cover over the city. Thus, the local weather was very hot and uncomfortable.

Besides, the northerly subsiding air brings hot weather, mainly because such northerly air subside after passing over mountains, and their warming and drying effect - the foehn effect - causes the temperature to rise further.