Some days; a few days — an expression referring to several unspecified days.
この町にいく日か滞在して観光するつもりです。
I plan to stay in this town for a few days and sightsee.
その問題については幾日か考えてから返事をしたい。
I'd like to think about that issue for a few days before answering.
いく日か雨が続いた後、ようやく晴れた。
After several days of rain, it finally cleared up.