January in Sliema is the rainiest and the windiest month of the year. In January, the weather in Sliema is typically warm. Average daily high temperature in January is about 15 degrees above zero. On average, Sliema has 17 sunny, 10 rainy, and 4 partly cloudy days in January. The rains are usually light. January as well as February is considered the most uncomfortable time to visit Sliema.