I often used to see a fox when I took Max for his afternoon walk about 13.00 he was always in the same are near the pond. I've not seen him for a while and I like to think that he's just changed his habits and nothing has happened to him.
Certainly as winter comes on, you do tend to see them out more and more during the day as food becomes scarcer. They're not purely nocturnal - it's just that night time is an easier time for them to hunt.