Montégut has an oceanic climate (Köppen climate classificationCfb). The average annual temperature in Montégut is 11.8 °C (53.2 °F). The average annual rainfall is 1,048.2 mm (41.27 in) with May as the wettest month. The temperatures are highest on average in July, at around 19.5 °C (67.1 °F), and lowest in January, at around 4.7 °C (40.5 °F). The highest temperature ever recorded in Montégut was 38.0 °C (100.4 °F) on 26 August 2010; the coldest temperature ever recorded was −12.3 °C (9.9 °F) on 8 February 2012.
Climate data for Montégut (1981−2010 normals, extremes 2008−2014)