The best months to visit Tonga are July and October. See monthly temperatures, rainfall and rain days (1991–2020 averages) to plan your trip.
Average daytime high and monthly rainfall in Tonga: January 28°C / 197mm; February 28°C / 215mm; March 28°C / 221mm; April 27°C / 163mm; May 27°C / 104mm; June 25°C / 102mm; July 24°C / 95mm; August 23°C / 110mm; September 24°C / 104mm; October 25°C / 97mm; November 25°C / 104mm; December 27°C / 119mm.