The Japanese word for temperature is
気温

きおん - kion
気-air, gas (ki), 温-warm (on)

Japanese Definition

temperature
1. 名詞. 温度、気温、体温

温度
1. n. temperature (a measure of cold or heat)

熱
1. n. fever
物凄い熱を出す - to come down with a terrible fever
2. n. (physics) heat
3. suffix. (informal) passion; mania; fever (towards an activity or topic)

気温
1. n. air temperature, atmospheric temperature, ambient temperature
(hyper, ja, 温度, tr=ondo)
(cot, ja, 水温, tr1=suion, 地温, tr2=chion)