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)

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)

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)