The high season for tourism on the Spanish island of Minorca and its city of Ciudadela is June through September when the weather is hottest.  Visitors flock to area beaches by the hundreds and crowd Ciudadela's streets, visiting its many shops and historic sites.  The average temperature during the summer on the island is in the mid-80's.  May and October are also nice times to visit, as the area is not quite as crowded and the weather is still warm.   

Cuidadela generally has mild winters, but has been known to get cold at times, requiring some warm clothing, but not usually dropping below freezing.  Tourists do not generally visit the city during the winter, but Ciudadela does have a thriving local population and most of the city's attractions are still open at that time for those who wish to see them.  For an up to date weather forecast on the island of Minorca visit Weather Underground's Minorca page.