Shirabe
何日 も

何日なんにち

Common Noun
English jmdict
1
noun (common) (futsuumeishi) what day
2
noun (common) (futsuumeishi) how many days
何日滞在する予定ですか。
How long are you going to stay?
English jmdict
1
adverb (fukushi) for many days;for several days
何日も続けて雨が降った。
It rained for several days on end.