Summer (June–September) is the main season. The weather is warm and dry, the trails in the Trinity Alps are clear of snow by late June, and Trinity Lake is warm enough for swimming. This is also when the town is most alive — the restaurants fill up, and the ranger station has its full staff and interpretive programs. Temperatures are comfortable at 2,000 feet even when the Central Valley is baking, rarely exceeding 95°F (35°C).
Spring and fall are quieter but rewarding. Wildflowers are good on the lower trails in May and early June; fall color in the Trinity Alps runs from late September through October. Snow usually closes the higher passes by November.
Winter can be harsh. Highway 299 stays open but can be icy; snow is common in town. The Joss House tours still run (though on reduced hours), and the quiet has its own appeal if you're staying several days. Most visitor-facing businesses keep shorter winter hours or close entirely.
One event worth timing a trip around: Weaverville holds a small Gold Rush Days celebration in late summer, with historical reenactments and activities near the Joss House.