weather in manassas, virginia fahrenheit
Virginia Weather > Manassas Weather. Manassas, VA climate is warm during summer when temperatures tend to be in the 70's and very cold during winter when temperatures tend to be in the 30's. The warmest month of the year is July with an average maximum temperature of 87.40 degrees Fahrenheit, while the coldest month of the year is January with an average minimum temperature of 21.90 degrees Fahrenheit.