The variety of weather conditions in Olympic National Park. B Bell NPS Photo. Weather in Olympic is variable and unpredictable, no matter the time of year. It is common for different weather conditions to exist within the park at the same time. Even in the summer, temperatures may vary from 10-20 degrees, especially along the coast and higher elevations. Always check the current weather forecast or call the park's weather hotline at 360-565-3131 before your visit.