There are two yachts harbour, one north (Mandraki) and the other south (Naok) of the city
was the old venetian harbour now turned into a yachts club, under the old citadel, through which you can reach the city center. Good shelter, only with strong NW wind becomes uncomfortable more than dangerous
GARITSAS bay, on the south side of Cape Sidhero provides a good shelter from prevailing NW wind. The anchorage is close southward of the old British garrison church of St. George, to be recognized by its handsome Doric facade. A yacht can anchor in 4-10 metres on mud, the above-waters rocks can be seen, a NAOK YACHT CLUB is close by.
More info : https://en.wikipedia.org/wiki/Corfu_%28city%29
Weather forecast : http://www.windfinder.com/forecast/corfu_city