New Plymouth's climate is mild and fairly rainy year-round, tempered by its coastal position. The best weather for mountain views and outdoor activities is from December to March (the New Zealand summer), when the days are longer and clearer. This is also when the Festival of Lights runs in Pukekura Park, and when the surf beaches are warmest — though the Tasman Sea is never exactly warm.
Winter (June to August) is when the mountain skiing at Manganui operates. The mountain is frequently cloud-covered in autumn, but there are clear spells throughout the year. Spring (September to November) brings rhododendrons and new growth in the park, and is a pleasant time to visit. Pack rain gear regardless of when you come.