For pleasant weather and outdoor activities, the best time to visit Castle Rock is generally from late spring to early fall, specifically May through September.During these months, the weather is typically mild and agreeable, with warmer temperatures and less rainfall, making it ideal for exploring the area's natural attractions. This period allows visitors to fully enjoy activities like hiking, fishing, and boating on the Cowlitz River.Families often find late summer, particularly August, an excellent time to visit. The consistent warm weather is superb for outdoor adventures, and many local attractions are in full swing. It's a great time for day trips to nearby natural landmarks or engaging in water-based activities.Couples looking for a more relaxed experience might prefer the shoulder months of May, early June, or September.