Chico has a classic valley climate: hot, dry summers and mild, sometimes foggy winters. The swimming holes in Bidwell Park are at their best in June and September, when the water is warm enough and the crowds thin out compared to July and August. Spring (March through May) is arguably the most beautiful time — the hills are green, the valley oak canopy is fresh, and the temperature is ideal for hiking.
Summer can be genuinely hot, with temperatures regularly above 100°F (38°C) in July and August. If you come in summer, plan outdoor activities for early morning and late afternoon. The Sierra Nevada Brewing Company's outdoor events and Bidwell Park's shade make the heat manageable.
Autumn brings the harvest. The almond and walnut harvest runs through September and October, and the Farmers Market is at its best with stone fruits, winter squash, and fresh-pressed olive oil. The National Yo-Yo Contest is held in October.