When I make a blog post should my keywords be specific to the blog post or the website?

Right now I’m running a series of posts, 365 things to do in the Twin Cities. I post something new to do each day. The posts aren’t really related to the website, but I’m not sure if I should use keywords that are specific to the website, in this case real estate or keywords specific the actual post, for example, a post about the minnesota zoo, should that post of keyword specific to the minnesota zoo?