The climate of Guam
Guam is an island situated in Oceania. Guam that counts 549 square
kilometers is not an independent country but a separate territory of
the United States of America. Guam belongs to the region of
Micronesia. The climate of Guam is a tropical rainforest climate,
which in the Köppen-Geiger climate classification is indicated with
the letter code Af. Guam has a drier and a wet season. This wet season
starts in July and lasts up to and including November. In this period
the amounts of precipitation can easily rise to three-hundred
millimeters per month and in some years even to nearly five-hundred
millimeters. As a rule most precipitation falls in the months of
August and September. On an average the month of March is the driest.
In March there is an average amount of rainfall of 89 millimeters. If
it rains in Guam this is often in the form of showers that can
sometimes be very heavy. The duration of the showers can sometimes be
very short. Therefore short heavy showers of less than a minute
regularly occur in Guam.
The maximum temperature in Guam is around 30-31 degrees actually
throughout the year. It does not get much warmer and actually there
are not many days in Guam that the temperature drops far below the
limit of thirty degrees. The difference within a 24 hours’day is also
not that big. The minimum temperature is between 23 and 27 degrees
centigrade throughout the year. During the wetter season the
temperature sensation is somewhat higher than during the drier months.
This is caused by an increase of the relative air humidity through
which it feels damper.
Guam lies in Typhoon Alley, an area where regularly develop
tropical storms. This happens particularly in the period of July up to
and including December. During that period there is a chance of Guam
being struck by heavy tropical storms. Sometimes there is a question
of a hurricane force that may have destructive consequences for Guam.
Thus the island has been struck several times by heavy hurricanes
(also called cyclones or typhoons). For instance, in 1976 the super
typhoon Pamela was the cause that wooden constructions in Guam were
replaced by concrete constructions. However this could not prevent the
super typhoon Pongsona from causing extremely much damage in Guam in
The figures below are based on registered weather information of
more than one year and are an average for Guam.
(locally slight deviations may occur).
More climate information
Climate figures come in handy but do not offer an overall picture of
the climate and the possible weather conditions within a particular
period. You cannot often find in figures how big the chance is of
wintry weather, (extreme) heat or hurricanes. Therefore we monthly
offer useful extra climate information.
The information at this site was carefully composed from climate data collected by meteorological services, meteorological offices, climate experts and other sources. “More climate info” is based on statistics, climate data and personal experience. No rights can be derived from this site. Weather has no memory and gives no guaranties. Nothing is as changeable and unpredictable as the weather. The authors of this site feel in no way responsible for any damages caused by misinterpretation or other circumstances that may influence your holiday or trip to a certain destination. We provide information, it’s up to the reader to use it to it’s benefit.