High rainfall and relatively warm weather makes for dense forestation right across the island. At latitude 47 degrees south (the "Roaring Forties") Stewart Island weather is often unpredictable. The climate is temperate with summer temperatures climbing to the mid-20's. Sunshine hours are equal to the national average.It’s a high rainfall area, between 1,000mm to 3,000mm per annum depending on elevation and aspect, but without rain, there’s no rainforest!
Approximately 80 percent of Stewart Island is set aside as the Rakiura National Park, New Zealand's newest national park.