May in Kamloops is the rainiest month of the year. In May, the weather in Kamloops is typically warm. Average daily high temperature in May is about 13 degrees above zero. On average, Kamloops has 20 rainy, 6 cloudy, 4 sunny, and 1 partly cloudy day in May. The rains are usually moderate. May as well as March, April, and June is considered the most uncomfortable time to visit Kamloops.