Guam's Climate

Guam's climate is pleasantly warm year-round. The mean annual temperature is 81 degrees; generally, the range is from the low 70s to the middle 80s. The coolest and least humid months, marked by prevailing westerly tradewinds, are in December through February. Although the warmest months are from March through August, the refreshing trade winds blow steadily. The annual rainfall totals 80 to 110 inches. There are two seasons, the dry and the rainy. The dry season, "fanumnangan," begins in December through June. The rainy season, "fanuchanan," falls within the remaining months.

Weatherjanfebmarapr mayjunjulaugsep octnovdec
Avg Fahrenheit76777879 7980808079 808079
Avg Centigrade24252626 2627272726 272726
rainfall inches5.164.262.974.03 4.495.199.5912.1614.08 14.408.515.85
rel humidity %77767574 7376768181 808078
sunshine hrs/day11.1511.3011.5112.16 12.4012.5813.0012.4712.24 12.0011.3511.18

Click here for a precise satellite picture via The Weather Service at Tiyan.
You will find a 300k gif satellite closeup of the Marianas.

Naval Joint Typhoon Warning Center Guam (click the JTWC Products)
The site for tracking typhoons when it approaches the Marianas.

Storms are generally grouped as:

The wind conditions are defined in one of four catagories:

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