Complex sentence: Apart from Kanazawa and Shizuoka it is the wettest sizeable city in Japan and indeed all of temperate Eurasia, and in the summer the heat and humidity can be very unpleasant, with wet-bulb temperatures sometimes reaching.
Split into simpler sentences: Apart from Kanazawa and Shizuoka it is the wettest sizeable city in Japan and indeed all of temperate Eurasia. In the summer, the combination of persistent heat and high humidity results in unpleasant conditions, with wet-bulb temperatures sometimes reaching.