A rainforest is a forest that by definition experiences high annual rainfall. Rainforests are divided into two subsets: tropical rainforests and temperant rainforests. This differentiation is made because of differences in climate, weather and location. Tropical rainforests are located in tropical regions, and temperate rainforests are found in higher latitudinal regions.
All rainforests have a high annual rainfall and this is the key characteristic that makes them a rainforest. Rainforest climates can be tropical or seasonal. The minimum annual rainfall for a tropical rainforest is between 68 and 78 inches. The minimum precipitation for a temperate rainforest is about 50 inches.
Tropical Rainforest Climate
Tropical rainforests are located within 10 degrees of the equator. Through the year, they experience little variation in weather or daylight. The midday sun is nearly vertical in the sky all days of the year, and rain typically falls in the afternoon. Relative humidity is always high, typically somewhere close to 70 per cent.
Tropical Rainforest Temperatures
The average temperature of a tropical rainforest is about 25 degrees C. The rainforest stays about this temperature year round. In fact, the temperature difference between night and day is greater than the difference in temperature from any two days in the year. Extensive cloud cover and heavy rainfall keep temperatures from getting considerably hotter or colder. On the low end, a temperature in a tropical rainforest below 17.8 degrees C would be very rare.
Temperate Rainforest Climate
One key difference between tropical and temperate rainforests is climate variability. A temperate rainforest experiences all four seasons and a part of the rainfall count falls in the form of snow. Temperate rainforests are found between an ocean and a mountainous region, like the western sides of the Rocky Mountains in North America and the Andes in South America. The cloud moisture from the ocean 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 10 degrees C. In the summer, temperatures can reach more than 26.7 degrees C and in the winter, temperatures can drop to below freezing. Mild temperatures are characteristic of early fall, late spring and most of the summer.