Climate Insights for Koumac

The climate in Koumac is warm and mild. The average annual temperature is 24°C and approximately 1081mm of precipitation falls per year. February is the wettest month, receiving around 196mm of rainfall. Koumac 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: January, February, March. The coldest months are August, July, September, when temperatures can drop to 19°C.

Koumac has relatively stable temperatures year-round, staying within a 10°C range. The warmest month is January, when average highs reach 29°C and the mean temperature sits around 27°C. August is the coolest month, with minimum temperatures around 19°C and an average of 21°C. Daily temperature variation is modest, with an average difference of 5°C between highs and lows.

Koumac is a moderately rainy area, receiving approximately 1081mm of precipitation annually, which averages out to around 90mm per month. The wettest month is February, averaging 196mm of rainfall. January and March also tend to see above-average precipitation. The driest month is September, with just 26mm. That's 170mm less than February, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

Koumac is mildly breezy, with an average annual wind speed of 12km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is August, averaging 13km/h, though still comfortable for most outdoor activities. The calmest conditions occur in March, with average winds dropping to 11km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 2km/h between the calmest and windiest months.

It is currently spring in Koumac, which began on September 23, 2026. Koumac 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 January at around 29°C, while the coldest stretch bottoms out in August near 19°C. Summer is next, beginning on December 21, 2026 (87 days from now).

The best time to visit Koumac is during May, June, July, August, September and October, when the weather is most comfortable for travellers. During these months, average temperatures hover around 23°C with modest rainfall averaging 41mm per month. By contrast, January can be uncomfortably hot with temperatures reaching 29°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 Koumac 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.