I like MIwa-san’s correction the most.
Especially the last part.
「もっと」sounds like very infant language「ぐっと」is an excellent choice and it still has casual sound. If you want little bit formal written language, you could consider 「さらに」.
夜になりさらに(or ぐっと)冷えこんできたので
夜になり寒さが厳しくなってきたので
「夜ご飯」could be used when we speak. 「晩御飯 」「夕飯」are casual alternatives. If you prefer formal expression 「夕食」(Miwa-san used this one) or 「夕餉(ゆうげ)」 would be your options.
You could, however, write varied ending of the sentences. 「した」is good. 「です」would be also and you could end sentence with noun. That's called「体言止め」
Good luck with your study!