good question! It's because of the influence of the English word/concept "weekend". Basically, we tend to translate the english neutral gender into masculine. So "weekend" would be masculine. So the literal translation "fine settimana" is masculine as well. Counterintuitive, since "LA fine"=the end is definitely feminine. ("IL fine" also exists but it means "the purpose", so, it's unrelated !) Conclusion ! You can say either IL fine settimana o LA fine DELLA settimana.