December in Valletta is the windiest month of the year. In December, the weather in Valletta is typically warm. Average daily high temperature in December is about 16 degrees above zero. On average, Valletta has 13 sunny, 11 rainy, 6 partly cloudy, and 1 cloudy day in December. The rains are usually heavy. December as well as January and February is considered the most uncomfortable time to visit Valletta.