In a year, the rainfall is 1140 mm | 44.9 inch. June, the first month of the summer in Martinsville, is a moderately hot month, with temperature in the range of an average high of 79.9°F and an average low of 63°F. With the onset of June, the average high-temperature subtly transitions from an agreeable 72.1°F in May to a warm 79.9°F.