It is cooler along the coast, than brief bits where you are inland. The ocean currents keep things cool, but also moderate against large temperature swings.
Using Fort Bragg as a proxy for climate averages:
https://weatherspark.com/y/364/Avera...tes-Year-Round and Eureka to cross check:
https://weatherspark.com/m/314/8/Ave...-United-States Suggests average highs of 72F (22C) and lows of 52F (11C) with a fairly tight range. I typically plan for extremes reaching about the 90th percentile or ~45F (7C) with what I bring just in case - so depends a bit on what sleeping bags you have. You could also have warmer than average nights, but I wouldn't expect much above 59F (15C) at night.
Expect some cool evenings, some fog and comfortable daytime temperatures. Nights should be cool along the coast, but not extremely cold.