In June, the weather in Coquitlam is typically warm. Average daily high temperature in June is about 15 degrees above zero. On average, Coquitlam has 18 rainy, 5 sunny, 4 cloudy, and 3 partly cloudy days in June. The rains are usually heavy. June as well as January, February, March, and April is considered the most uncomfortable time to visit Coquitlam.