Along the CA and Oregon coast -- avoid the summer if you want to avoid fog. September and early October is the best weather of the entire year. Spring (late April/May) can be very nice too. Right along the coast-heat is almost never an issue.y partner and I want to plan a trip form Austin, Texas up to Seattle via the West Coast next year, in 2015. We would like to travel when it is warm to hot, but not during the August holidays.