The best months to visit Guam are February and March. See monthly temperatures, rainfall and rain days (1991–2020 averages) to plan your trip.
Average daytime high and monthly rainfall in Guam: January 29°C / 74mm; February 29°C / 57mm; March 30°C / 48mm; April 31°C / 74mm; May 31°C / 89mm; June 31°C / 148mm; July 30°C / 292mm; August 31°C / 372mm; September 30°C / 341mm; October 29°C / 300mm; November 31°C / 179mm; December 31°C / 100mm.