December in Seabrook is the rainiest and the cloudiest month of the year. In December, the weather in Seabrook is typically warm. Average daily high temperature in December is about 16 degrees above zero. On average, Seabrook has 17 rainy, 8 sunny, 5 partly cloudy, and 1 cloudy day in December. The rains are usually heavy. December as well as July and September is considered the most uncomfortable time to visit Seabrook.