The entire Nelson/Tasman region has a warm climate around the year but experiences all seasons. Average summer temperatures in Nelson Lakes National Park range from 12°C to 24°C and may peak up to 30°C. Average winter temperatures drop between 2°C and 13°C and may even reach up to -10°C, mostly depending on altitude.
Nelson Lakes is less affected by heavy annual precipitation than the west coast and experiences between 7 and 10 rain days a month. Due to the park's altitude, visitors are warned to prepare for rapidly changing weather conditions that may even affect the surrounding lowlands.