天魚[amago] land-locked variety of red-spotted masu trout (Oncorhynchus masou ishikawae)
御天気[otenki] weather
コール天[kooruten] corded velveteen
破天連[pateren] Portuguese Jesuits (in Japan in the 16th century)
天鵝絨[tengajuu] velvet

悪天[akuten] bad weather
悪天候[akutenkou] bad weather
悪天使[akutenshi] evil angels
旭日昇天[kyokujitsushouten] full of vigor and vitality (like the rising sun) (vigour)
一天[itten] the whole sky

陰晴[insei] unsettled (fine and cloudy) weather
快晴[kaisei] clear weather
気晴し[kibarashi] recreation
見晴し[miharashi] view
見晴す[miharasu] to command a view

五月晴[satsukibare] early-summer fine weather (during rainy season)
晴らす[harasu] to dispel
晴れる[hareru] to clear up
晴間[harema] break (in the weather, esp. rain or snow)