In terms of precipitation, rainfall in Tongatapu ranges from 3.7 - 8.3 inches per month. February is typically the wettest month, when rainfall can reach 8.3 in. June is typically the driest time to visit Tongatapu when rainfall is around 3.7 in.
If weather is an important factor for your trip to Tongatapu, 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 71.6 F).