Climate Insights for Chatham Island

The climate in Chatham Island is temperate. The average annual temperature is 13°C and approximately 784mm of precipitation falls per year. Chatham Island receives a notable amount of rainfall throughout the year, including during its driest month. Chatham Island is in the Southern Hemisphere. The seasons are reversed — summer runs from December to February, while winter falls between June and August. The summer months are: February, March, January. The coldest months are August, September, July, when temperatures can drop to 10°C.

Chatham Island has relatively stable temperatures year-round, staying within a 7°C range. February is the warmest month, though highs remain moderate at 17°C with a mean of 16°C. August is the coolest month, with minimum temperatures around 10°C and an average of 10°C. Daily temperature variation is modest, with an average difference of 2°C between highs and lows.

Chatham Island is a relatively dry area, receiving approximately 784mm of precipitation annually, which averages out to around 65mm per month. The wettest month is July, averaging 94mm of rainfall. August and March also tend to see above-average precipitation. The driest month is January, with just 39mm. That's 55mm less than July, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.

Chatham Island is very windy, with an average annual wind speed of 39km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is July, averaging 45km/h, which can feel quite blustery and may affect outdoor activities. The calmest conditions occur in February, with average winds dropping to 35km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 10km/h between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 43km/h in winter, 40km/h in spring, 35km/h in summer, 39km/h in autumn.

It is currently autumn in Chatham Island, which began on March 20, 2026. Chatham Island is in the Southern Hemisphere, where the seasons are reversed — spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in February at around 17°C, while the coldest stretch bottoms out in August near 10°C. Winter is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Chatham Island is during January, February and March, when the weather is most comfortable for travellers. During these months, average temperatures hover around 15°C with modest rainfall averaging 53mm per month. By contrast, August can be quite cold with temperatures dropping to 10°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Chatham Island based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.