July in Newmarket is the rainiest and the warmest month of the year. In July, the weather in Newmarket is typically warm. Average daily high temperature in July is about 20 degrees above zero. On average, Newmarket has 22 rainy, 5 sunny, 2 cloudy, and 2 partly cloudy days in July. The rains are usually heavy. July as well as January, February, March, and April is considered the most uncomfortable time to visit Newmarket.