The climate is characterized as tropical marine. The weather is generally hot and very humid with little seasonal temperature variation. The mean high temperature is 86°F (30 °C) and mean low is 74°F (24 °C) with an average annual rainfall of 96 inches (2,180 mm). The dry season runs from December through June. The rainy season starts in July and continues through November. The months of January and February are considered the coolest months of the year with nighttime temperatures in the mid to low 70's and generally lower humidity levels. The highest risk of typhoons is during October and November, however, typhoons can occur at any time of the year.

An average of three tropical storms and one typhoon pass within 180 nautical miles (330 km) of Guam annually. The most intense typhoon to pass over Guam recently was Super Typhoon Pongsona, with sustained winds of 125 miles per hour, which slammed Guam on December 8, 2002, leaving massive destruction. Since Super Typhoon Pamela in 1976 wooden structures have been largely replaced by concrete structures. During the 1980s wooden utility poles began to be replaced by typhoon-resistant concrete and steel poles. In the 1990s many home and business owners installed typhoon shutters.

Source: Wikipedia, the free encyclopedia