Temperate rainforests are found on the wet, mild edges of continents, primarily along coastlines where ocean moisture meets mountain barriers. They exist on every continent except Africa and Antarctica, but the largest stretches run along the Pacific coast of North America and the southern coast of Chile. Compared to their tropical counterparts, temperate rainforests are rare, covering a small fraction of Earth’s land surface and concentrated in surprisingly narrow coastal strips.
Why Temperate Rainforests Form Where They Do
These forests need two things: heavy rainfall and mild temperatures year-round. Average precipitation runs about 55 inches per year but can reach 100 inches in wetter zones. Temperatures stay moderate, rarely dropping below freezing, and typically average between 39°F and 54°F across the year. That combination of constant moisture and cool-but-not-cold air only occurs in specific geographic situations.
The key mechanism is orographic lifting. Moisture-laden air blows in from the ocean and hits a coastal mountain range, forcing it upward. As the air rises, it cools and drops enormous amounts of rain on the ocean-facing slopes. This is why nearly every temperate rainforest on Earth sits between an ocean and a mountain range. The mountains also block that moisture from moving inland, which is why these forests form narrow ribbons rather than broad expanses.
North America: The Pacific Coast Corridor
The largest temperate rainforest region in the world stretches along the Pacific coast of North America, from southern Oregon through Washington State, British Columbia, and into southeast Alaska. A significant portion occurs in British Columbia, Canada, making it one of the most important temperate rainforest regions globally. Olympic National Park in Washington contains some of the most iconic examples, where annual rainfall in certain valleys exceeds 12 feet.
This corridor once formed a nearly continuous band of forest, but little remains outside of protected areas. Logging through the 19th and 20th centuries fragmented much of the original range. The forests that survive are dominated by massive conifers, some over 200 feet tall, draped in thick layers of mosses and ferns. Fallen trees become “nurse logs” that support new growth, creating the layered, green-on-green look that defines these ecosystems.
South America: Chile’s Valdivian Forests
Chile’s southern coastline holds the largest temperate rainforest in the Southern Hemisphere. Known as the Valdivian temperate rainforest, it runs along the coast in regions like Los Ríos, where the Andes and coastal mountain ranges trap Pacific moisture in much the same way the Cascades do in North America. The Valdivian Coastal Reserve alone covers about 50,000 hectares (roughly 123,500 acres) in the Pelada Mountain Range.
These forests are ancient in a deep geological sense. They were once connected to the forests of New Zealand and Australia when those landmasses were joined as part of the supercontinent Gondwana. That shared ancestry explains why similar plant families appear across all three regions despite being separated by thousands of miles of ocean. Chile’s forests include the alerce tree, a slow-growing conifer that can live for over 3,000 years, now protected within Alerce Coastal National Park.
Australia and New Zealand
Tasmania, the island state off Australia’s southeastern coast, contains temperate rainforests with some of the oldest plant lineages on Earth. Several ancient conifer species found there trace their ancestry back to the Jurassic period, over 145 million years ago. Tasmania’s combination of high biodiversity, varied terrain, and ocean-moderated climate makes it a concentrated hotspot for this biome, though the forests occupy a relatively small area compared to North or South American examples.
New Zealand’s South Island, particularly the western coast facing the Tasman Sea, holds temperate rainforests shaped by the same Gondwanan heritage as Tasmania and Chile. The Southern Alps force moisture upward as it arrives from the ocean, producing the heavy rainfall these forests require. Some areas on New Zealand’s west coast receive over 200 inches of rain per year.
Europe’s Scattered Remnants
Europe once had more extensive temperate rainforest, but centuries of land clearing reduced it to small, scattered fragments. Remnant patches survive in parts of the United Kingdom and Norway, typically along western coastlines exposed to Atlantic moisture. In the UK, fragments cling to the coasts of Scotland, Wales, and western Ireland, where mild Gulf Stream temperatures and persistent rainfall create the right conditions. Norway’s western fjord coast supports similar remnants.
These European patches are tiny compared to the forests of the Pacific Northwest or Chile. Because so little remains, conservation efforts in Europe focus primarily on restoration and reforestation rather than simply protecting existing stands.
East Asia
Smaller temperate rainforests exist in Japan, where ocean moisture and mountainous terrain replicate the coastal dynamics found elsewhere. These forests occupy portions of the Japanese archipelago where warm ocean currents moderate temperatures and deliver consistent rainfall. Like Europe’s remnants, Japan’s temperate rainforests are limited in extent compared to the major regions in the Americas and Australasia.
How They Differ From Tropical Rainforests
The word “rainforest” makes many people picture the Amazon or Borneo, but temperate rainforests are a fundamentally different environment. Tropical rainforests sit near the equator and stay warm year-round, with temperatures averaging above 70°F. Temperate rainforests are cooler, sitting at higher latitudes (generally between 37° and 60° from the equator) where distinct seasons exist even if winters are mild.
The biodiversity profile is different too. Tropical rainforests hold the highest species counts on Earth. Temperate rainforests have fewer species overall but produce enormous biomass. The trees grow larger and live longer, and the sheer weight of living material per acre can actually exceed that of tropical forests. The thick carpets of moss, lichen, and ferns that coat every surface are a hallmark of temperate rainforests, thriving in the cool, perpetually damp conditions that would be too cold for most tropical species.
Why These Forests Are Shrinking
Temperate rainforests are among the most threatened forest types on the planet, largely because they occupy the same mild, coastal areas that humans prefer to settle. Logging, agriculture, and urban expansion have reduced global temperate rainforest cover dramatically, particularly in Europe and parts of North America.
Climate change poses a newer threat. Warmer temperatures and shifting precipitation patterns are projected for the North Pacific coast, with rainfall increasingly arriving as rain rather than snow. That shift, combined with a projected increase in wildfire frequency, is expected to raise tree mortality and shrink temperate rainforests at their warmer, drier edges. In Tasmania, rising temperatures and more frequent fires have already damaged ancient stands that took millennia to develop and cannot regenerate quickly.