In terms of precipitation, rainfall in Koumac ranges from 1.1 - 7.0 inches per month. January is typically the wettest month, when rainfall can reach 7.0 in. October is typically the driest time to visit Koumac when rainfall is around 1.1 in.
If weather is an important factor for your trip to Koumac, use this chart to help with planning. For those seeking warmer temperatures, February is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of July, when temperatures are typically at their lowest (around 68.0 F).