Summers on the west coast are cooler, cloudier, and wetter than adjacent regions to the south and east, such as the communities of Port Alberni, Nanaimo, Victoria or Vancouver. Winds are usually light and predominantly from the west-northwest, flowing somewhat parallel to the coast. Approximately 300 hours of sunlight can be expected for most Julys. The average mean temperature is about 17 degrees Celsius. Sea fog during July and August, and even into September, develops frequently.
Autumn marks the beginning of the wet season for the park.
With increasing cloud blocking the sun, temperatures drop considerably. Strong and persistent southeasterly winds bring frequent and severe storms, typically followed by the passage of a coldfront. Winter intensifies the wet autumn pattern. Average temperatures for the season range from a mean of 5 degrees Celsius to near freezing. Although there can be occasional wet snowfalls, snow is infrequent along this coast.