Taking into account the local weather in Otaki is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually August and July with an average temp of 69°F, while the coldest months are January and February with an average of 34°F. The rainiest months in Otaki are July, June, September, and August, with each month seeing an average of 13 inches of rainfall.