While I question the grammatical correctness of this passage, futur prochaine of these weather terms would be as follows:
...il va faire du soleil et il va faire chaud....le temperature va faire 15 degres....et le temperature pendant le nuit va faire 20 degres.
Futur prochain is the "near future" = "aller + l'infinitive. It is equivalent to our use of "going to" or "about to" + an infinitive as in the sentence It is going to be hot tomorrow. Since expressions about weather in French are idiomatic and make use of the verb "to do/make"/faire, you will conjugate "aller=to go" into the present tense, followed by the infinitive "faire," NOT "etre."