Constanza has an oceanic climate (Koppen climate classification Cfb), with moderately warm and humid summers, and dry and mild winters, due to its tropical location and high elevation. The average annual temperature varies from less than 10 °C in highlands to 18 °C in town.
In summer, temperatures range between 25 °C to 27 °C during the day, and between 12 °C to 15 °C at night. Wildfires are relatively common.
In winter, the temperatures are between 21 to 24 °C at day, and 8 to 12 °C at night. Fog is quite common. The last time that Constanza had freezing temperatures was on 1958; while in Valle Nuevo freezes are usual. Snow can fall in the highest peaks of Valle Nuevo, but it is becoming a rare event and accumulation almost no longer occurs.
The highest temperature ever recorded in town was 32.5 °C, on October 3, 1957. The coldest temperature was –1 °C, recorded on February 6, 1958
