www.justzante.co.uk is another good site. This question has been asked before so try doing a search in the travel section by typing in the category search box Zante and see what comes up!
Or try typing in ZAKYNTHOS which is the actual name of the island and you're bound to get a lot more results. yahoo has a good weather site. Was in ZAKYNTHOS in July and it was low 30s. My friend is going tomorrow and its supposed to be high 20s at the moment. I think it rains a lot there in Winter.