It grows best where fog moderates the typical summer drought conditions. Here, winters are usually mild with abundant rain. Frost is common, but hard freezes and snow are unusual.
Coast redwoods grow best only as far inland as the extend of the coastal maritime climate.
Here, fog often protects the trees from searing summer heat and freezing winter cold. Fog plays an important role in the survival of these trees, and pockets of inland trees usually coincide with foggy canyons. Redwoods can even generate their own fog, using the huge amounts of transpiring moisture that condense at night above the cool valley groves. Each large redwood can release up to 500 gallons of water per day into the air from their needles. As the air cools each evening, this moisture condenses into fog that protects the forest much like a blanket, keeping the day's heat trapped below.