Montfort-sur-Argens has a hot-summer Mediterranean climate (Köppen climate classification Csa). The average annual temperature in Montfort-sur-Argens is . The average annual rainfall is with November as the wettest month. The temperatures are highest on average in July, at around , and lowest in January, at around . The highest temperature ever recorded in Montfort-sur-Argens was on 28 June 2019; the coldest temperature ever recorded was on 8 January 1985.
