。
Hokkaido is really cold compared to Kyushu.
Literal
Hokkaido [topic-は] Kyushu [with-と] compare-[when-と] very cold.
比べる ('to compare') in the te-form 比べると creates a participial 'when compared to' — a fixed comparison phrasing. The と after 九州 marks the comparison partner. 九州 is the southernmost of Japan's four main islands, contrasting maximally with northernmost Hokkaido for climate.