Guam climate guide

Read our complete guide to the climate in Guam.

Temperature
Rainfall
Sunshine & daylight
UV levels & humidity
Climate overview

Temperature in Guam (°C)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Max temperature (daytime)	30	30	30	31	31	31	31	31	31	31	31	30
Min temperature (night-time)	24	24	24	24	25	25	25	25	25	25	25	24
Sea temperature	28	27	27	28	28	29	29	29	29	29	29	28

Sunshine & Daylight in Guam

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Daily hours of sunshine	6	6	7	7	7	7	5	5	5	4	5	5
Daily hours of daylight	11	12	12	12	13	13	13	13	12	12	12	11

Rainfall in Guam

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Number of days with some rain	23	19	20	19	20	17	19	20	19	22	22	23
Average monthly rainfall (mm)	130	111	89	102	142	162	273	363	343	317	228	150

More climate for Guam

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV Index (Maximum)	10	11	11	11	11	11	11	11	11	11	10	9
Heat & Humidity	H	H	H	H	VH	VH	VH	VH	VH	VH	VH	H

Note: 0 = None, L = Low, M = Moderate, H = High, VH = Very high, E = Extreme

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Recommended for Guam

The climate guide for Guam, represented by Agana, (Agana) shows long term monthly weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Metric (°C / mm) | Imperial (°F / inches)

Guam climate overview

Guam is the most southerly island of the Marianas Archipelago, in the Pacific Ocean over 2,000 kilometres (1,250 miles) to the east of the Philippines. Colonial Spanish influences are still evident in the lively capital Agana, although Spain ceded Guam to the United States in 1898, and the American government now maintains two large bases on the island.

Tourism is Guam's leading industry, with visitors arriving mainly from Japan in search of duty free shopping. Though the island has some nice beaches the best is off-limits to non-military personnel.

The northern two-thirds of Guam consists of a raised rolling limestone plateau with pockets of dense jungle that give the island a truly tropical feel. The northern coast is rugged with cliffs dropping precipitously into the sea, where huge Pacific swells have hollowed out an intricate tunnel of sea-caves along the base.

The south of the island is basically volcanic with an elongated mountain ridge dividing the inland valleys and coastline. The far south widens into a landscape of high hills and valleys cut by streams and waterfalls. The rolling hills, which are steep in places are mostly grass-covered, with trees growing only in the protected more fertile valleys. The best beaches are found along the sheltered coastline of the west, home to blindingly white sand and coral reefs.

The climate is tropical with rainfall in all months becoming heavy during the peak rainy season from July to December. Rainfall eases during the drier season from January to June when March is usually the sunniest month. Temperatures are consistently warm or hot all year with high heat and humidity.

On the average, one typhoon passes close by Guam each year usually between the months of August and December.