August in Monrovia is the windiest and the coldest month of the year. In August, the weather in Monrovia is typically warm. Average daily high temperature in August is about 25 degrees above zero. On average, Monrovia has 30 rainy and 1 sunny day in August. The rains are usually heavy. August as well as March, April, May, and June is considered the most uncomfortable time to visit Monrovia.