Courniou has a warm-summermediterranean climate (Köppen climate classificationCsb). The average annual temperature in Courniou is 11.9 °C (53.4 °F). The average annual rainfall is 1,444.7 mm (56.88 in) with December as the wettest month. The temperatures are highest on average in July, at around 20.2 °C (68.4 °F), and lowest in January, at around 4.8 °C (40.6 °F). The highest temperature ever recorded in Courniou was 39.3 °C (102.7 °F) on 12 August 2003; the coldest temperature ever recorded was −15.5 °C (4.1 °F) on 16 January 1985.
Climate data for Courniou (1981–2010 averages, extremes 1971−2014)