subtropical
adj.describing a climate that is warmer than a temperate one but not as hot as a tropical one. It usually has warm summers and mild winters.
adj.relating to or characteristic of a climate that is intermediate between tropical and temperate, typically featuring warm to hot summers and mild winters.
“The city has a subtropical climate with very hot summers.”
“Many subtropical regions are famous for their citrus groves and warm, humid weather throughout the year.”
“The transition from a temperate to a subtropical climate often results in a significant increase in biodiversity, as species from both zones begin to overlap.”
“The region has an extreme subtropical monsoon climate, with scorching summer heat, heavy monsoon rain and frequent typhoons.”
“Pelagic sargassum is a type of brown seaweed that floats on the ocean surface and is naturally abundant in the Sargasso Sea, a region of the subtropical North Atlantic.”
From sub- + tropical.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.