Other facts from our historical weather data: Which is the warmest month in Upper Hutt? February has an average maximum temperature of 20°C (68°F) and is the warmest month of the year. Which is the coldest month in Upper Hutt? The coldest month is July with an average maximum temperature of 12°C (54°F). Which is the wettest month in Upper Hutt? October tops the wettest month list with 123mm (4.8 in) of rainfall. Which is the driest month in Upper Hutt? March is the driest month with 79mm (3.1 in) of precipitation. Which is the sunniest month in Upper Hutt? January is the sunniest month with an average of 234 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.