Earth has two classes of rainforests: tropical and temperate. Tropical rainforests are located between the Tropics of Cancer and Capricorn and remain frost-free all year, while temperate rainforests occur in higher latitudes where seasonal temperature variations are more pronounced. Wherever it is found, the characteristic of a rainforest that distinguishes it from any other forest on the planet is its higher-than-average rainfall.
According to Wordnet, a lexical database provided by Princeton University, a rainforest as one with heavy annual rainfall. Tropical rainforests tend to have higher annual rainfall than temperate ones. Tropical rainforests can have from 66 to 400 inches of rain a year, while the precipitation for a temperate rainforest is 60 to 200 inches per year.
Tropical Rainforest Climate
Because no tropical rainforest is more than 30 degrees of latitude distant from the equator, none is farther than 1,400 miles from it. Consequently, tropical rainforests experience little annual variation in weather or daylight. The midday sun is close to the midheaven every day of the year. Rain typically falls in the afternoon and relative humidity is always high, never falling below 80%.
Tropical Rainforest Temperatures
The average temperature of a tropical rain forest is about 77 degrees Farehnheit, and it varies little throughout the year, although they often do have a wet and dry season. In fact, the temperature difference between night and day is typically greater than the temperature difference between any two days in the year. Extensive cloud cover and heavy rainfall help to keep temperatures stable. It is rare for the temperature in a tropical rainforest to fall below 64 degrees Fahrenheit.
Temperate Rainforest Climate
One key difference between tropical and temperate rainforests is climate variability. A temperate rainforest experiences all four seasons, and a certain percentage of precipitation falls in the form of snow. Most temperate rainforests are found between an ocean and a mountainous region, such as those west of the Rocky Mountains in North America or west of the Andes in South America. Atmospheric moisture gets caught between the ocean and the mountains and then falls over these rainforest areas.
Temperate Rainforest Temperatures
Temperatures in a temperate rainforest are mainly cool and wet, though they can get hot in summer. The average annual temperature is 50 degrees Fahrenheit. In the summer, temperatures can reach more than 80 degrees Fahrenheit, and in the winter, temperatures can drop below freezing. Mild temperatures are characteristic of early fall, late spring and most of the summer.