kikou = climate 1. The climate has gradually (dandan) been getting warmer. 2. The climate has started to gradually warm up. I think #2 is the better option.

It means "Here, the weather is just getting warmer and warmer." Let me know if you need further explanation:) ============ Kochira dewa : "kochira" is polite version of "koko" (here, this place). "Kochira dewa" means here in contrast with other place. kikou ga : "kikou" is climate. "Ga" is a particle for subject. dandan: adverb. "gradually" atatakaku natte: "atatakaku naru" is to become warm. "naru" is changed to te-form in order to connect to "kimashita". ki mashita : literally means "come." It's used to express that some change started, and it has been kept changing until now.