In December, the weather in Bandar Seri Begawan is typically warm. Average daily high temperature in December is about 27 degrees above zero. On average, Bandar Seri Begawan has 28 rainy and 3 cloudy days in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Bandar Seri Begawan.