Although weather is just one factor, it can really affect your travel plans, especially if you are planning a longer stay in Morristown. The hottest months are usually July and August, with an average temperature of 20°C, while the coldest months are January and February, with an average of -6°C. The snowiest months in Morristown are March, January, February and April, with each month seeing an average of 13 cm of snowfall.