When to Go

The park is open year-round, though most roads—the main exception being Lassen Park Highway up to Kohm Yah-mah-nee Visitor Center—are closed from late October to mid-June due to snow. The park's high elevation offers a cool respite in summer from California's hot central valley, while spring and fall are typically mild during the day, but you should prepare for lows below freezing at night even in June and September.