January in Blenheim is the windiest and the warmest month of the year. In January, the weather in Blenheim is typically warm. Average daily high temperature in January is about 20 degrees above zero. On average, Blenheim has 14 partly cloudy, 13 sunny, 3 rainy, and 1 cloudy day in January. The rains are usually light. January as well as February and March is considered the most comfortable time to visit Blenheim.