"Today is sunny too."
Actually you can. はれ as a noun here. Compare the noun form and the verb form:
I think you mixed up the two concepts. …が…に…いる is the construct for the existance of animated subjects.
However …ている has two different meanings and is different from above.
Action verb + ている means the continuous action of the verb..e.g. 見ている "is looking," 食べている "is eating."
State verb + ている means the continuous state of the verb. e.g. 始まっている=始まった "something started/is starting," 着いている=着いた "someone arrived," 終わっている=終わった "something finished."
います does not only mean the existance of animate subjects, but it is used as a auxiliary verb in ている, which denotes either the main verb is in a continuous state, or is in a continuous action. Please see my other comment for details.
Anyone else got confused by も vs もう? I learnt the latter form up until now, but that might either be just plain wrong or more like "も with emphasis"?
I was marked wrong for putting MO at the beginning of the sentence. Does KYOU have to go first?