Climate and monthly weather forecast
Hagåtña, GU

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The climate of Hagåtña

Hagåtña, the capital city of Guam, a U.S. territory located in the western Pacific Ocean, has a tropical rainforest, otherwise known as Af classification according to Köppen climate scheme. The weather displays slight variations in climatological conditions throughout the year, characterized by relative humidity close to 77% throughout the year. Moreover, there are minimal fluctuations in temperature, with monthly averages ranging from 81.1°F (27.3°C) to 82.9°F (28.3°C) for minimum temperatures, and from 82.6°F (28.1°C) to 84.7°F (29.3°C) for maximum temperatures.

Sea temperatures experience only mild fluctuations between 82°F (27.8°C) and 85.4°F (29.7°C). With almost no seasonal variability, the annual average sunshine hours per day oscillate between 6.3h to 10.6h, and daylight hours, from 11.3h to 12.9h. Rainfall shows interesting patterns, it gradually increases through the year, reaching its peak between July to September, with monthly averages varying from 1.81" (46mm) to 10.28" (261mm). July, August, and September observe the highest rainfall. The wind conditions also fluctuate between 9.6mph (15.4km/h) and 16.3mph (26.2km/h).

The best time to visit Hagåtña

Considering the climatic tendencies of Hagåtña, the most favorable time for visitation would be between February and May. During these months, rainfall is relatively low, ranging from 1.81" (46mm) to 3.31" (84mm), and sunshine hours reach their peak, varying from 8.1h to 10.6h per day. Furthermore, temperatures remain pleasant—between 79.7°F (26.5°C) and 82.2°F (27.9°C)—with sea temperatures also remaining warm, from 82°F (27.8°C) to 84°F (28.9°C), ideal for water activities.

The worst time to visit Hagåtña

The least favorable time to visit Hagåtña is between July and September. These months register the highest rainfall, from 7.52" (191mm) to 10.28" (261mm), with increased cloud cover, reducing sunshine hours to between 7.6h and 8.6h per day. Also, the wind strength intensifies during these months, ranging from 9.6mph (15.4km/h) to 10.3mph (16.6km/h). High humidity levels coupled with increased rainfall make outdoor activities challenging.

Spring weather in Hagåtña

The spring months in HagåtñaMarch, April, and May—bring comparatively moderate weather conditions. Rainfall is relatively low, ranging from 1.81" (46mm) to 3.31" (84mm). Average high temperatures hover around 82°F (27.8°C) to 84.2°F (29°C), while the average lows stay within a comfortable 80.1°F (26.7°C) to 82.2°F (27.9°C). The sunshine duration varies from 8.1h to 10.6h, with daylight available for approximately 12.1h to 12.7h each day.

Summer weather in Hagåtña

Summer in HagåtñaJune, July, and August—is typically wet, with monthly rainfall peaking from 3.7" (94mm) to 9.76" (248mm). Despite the wet conditions, temperatures remain relatively stable, with maxima from 84.6°F (29.2°C) to 84.7°F (29.3°C), and minima from 82.2°F (27.9°C) to 82.9°F (28.3°C). The sea temperature remains warm, ranging from 84.8°F (29.3°C) to 85.4°F (29.7°C). This period experiences fewer sunshine hours—between 7.6h and 10.6h—and average daylight hours oscillate around 12.8h to 12.9h.

Autumn weather in Hagåtña

Autumn—September, October, and November—maintains high rainfall levels with average monthly precipitation ranging from 4.69" (119mm) to 10.28" (261mm). Yet, the temperatures stay largely consistent, with the maximum ranging between 84.2°F (29°C) and 84.4°F (29.1°C), and the minimum temperature varies from 82.4°F (28°C) to 82.8°F (28.2°C). Sea temperatures around this time range from 84.5°F (29.2°C) to 85°F (29.4°C), offering pleasant conditions for water-based activities.

Winter weather in Hagåtña

Winters in HagåtñaDecember, January, and February—see a reduction in rainfall, with average precipitation values dropping to between 2.28" (58mm) and 2.99" (76mm). The cool sea temperatures, ranging from 82°F (27.8°C) to 83.2°F (28.4°C), complement the moderate air temperatures—with maximum values from 81.7°F (27.6°C) to 84°F (28.9°C), and minimums from 79.7°F (26.5°C) to 82°F (27.8°C). Noteworthy are the longer sunshine hours, varying from 6.3h to 7.6h, during this period.

Weather in January

Step into the new year in Hagåtña, Guam with a pleasant tropical climate, dominating the city throughout the month. Here, the days remain warm, though the evenings bring a couple of degrees drop providing a comfortable respite. Weather in January »

Weather in February

Moving into February, Hagåtña continues to enjoy its tropical climate, basking in sunshine over the days and relaxing with mild evenings. While the city encounters an average of 17.5 days of rainfall yielding an accumulated 2.28" (58mm), it poses little hindrance to outdoor events. Weather in February »

Weather in March

March draws the curtain on winter and welcomes the upcoming spring season. Hagåtña, Guam prides itself on its consistent tropical weather, ensuring warm days and balmy evenings throughout the month. As the city prepares for spring, frequent, short spells of rain provide a welcome change. Weather in March »

Weather in April

The climate in April remains harmonious with earlier months, earning Hagåtña the honour of year-round tropical paradise. Whether exploring the city's heritage or devouring its culinary treats, the weather in April ensures a pleasant experience. Weather in April »

Weather in May

May ushers in the city's slight summer surge, humidity levels remain steady and the temperatures creep a little higher. Outdoor enthusiasts can appreciate the city's serene beaches, delicate rainforests, and vibrant festivals during this month. Weather in May »

Weather in June

As the rest of the world embraces summer, Hagåtña, Guam retains its characteristic tropical environment into June. Visitors can relish the balmy weather while exploring the city's cultural attractions and natural landmarks. Downpours become slightly more frequent, culminating in an accumulated rainfall of 3.7" (94mm) across a spread of 25.4 days. Weather in June »

Weather in July

July signifies the height of summer, a season typically associated with scorching heatwaves. Yet, the tropical paradise of Hagåtña remains impervious to this trend. Showers become abundant with a recorded high rainfall of 7.52" (191mm) spanning over 28.9 days, amounting to one of the wettest months of the year. Weather in July »

Weather in August

August rolls in promising hot days, but Hagåtña, Guam offers a pleasant surprise with its moderate tropical climate. Brace for generous rain showers, as this month sees the highest rainfall of the year, amounting to a staggering 9.76" (248mm) over 28.9 days. Weather in August »

Weather in September

September in Hagåtña, Guam, delivers yet another month of moderate tropical weather marked by hot days and cool nights. This is an ideal period for visitors looking to immerse in the local traditions and community gatherings. Weather in September »

Weather in October

As October sets in, the pace starts to gently slow down in Hagåtña. The tropical comfort persists and the showers diminish, allowing more opportunities for outdoor activities and exploration. Despite the intermittent downpours, scoring 8.46" (215mm) of rainfall over 28.7 days, the overall atmosphere remains exhilarating. Weather in October »

Weather in November

November brings a subtle change to Hagåtña’s weather pattern. While remaining largely tropical, there's a slight reduction in rainfall and a hint of a cooler breeze. The city enters a calming phase, before preparing for the full zeal of the festive season. Weather in November »

Weather in December

Welcoming December, Hagåtña, Guam presents a delightful medley of warm tropical weather and seasonal festivities. The city starts bracing for the holiday season with an air of anticipation and joy. A further reduction in rainfall to 2.99" (76mm) over 22.8 days provides the perfect backdrop for holiday shopping, Christmas parades, and festive celebrations. Weather in December »
Updated: Jul 16, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the most humid month?

The months with the highest humidity are January, March through May, October through December, with an average relative humidity of 78%.

How much does it rain?

Throughout the year, there are 288.5 rainfall days, and 60.08" (1526mm) of precipitation is accumulated.

When is the highest UV index?

January through August, October through December, with an average maximum UV index of 7, are months with the highest UV index.

What is the coldest month?

February is the coldest month, with the temperature often reaching an average high of 81.7°F (27.6°C) and an average low of 79.7°F (26.5°C).

What is the month with the coldest ocean?

With an average ocean temperature of 82°F (27.8°C), February is the month with the coldest seawater.

What is the driest month?

March is the month with the least rainfall. Rain falls for 20.2 days and accumulates 1.81" (46mm) of precipitation.

When are the longest days?

With an average of 12h and 54min of daylight, June has the longest days of the year.

What month has the most sunshine in Hagåtña?

June has the most sunshine of the year, with an average of 10.6h of sunshine.

What is the hottest time of year in Hagåtña?

The months of July and August are noted for their peak temperatures, with an average high-temperature of 84.7°F (29.3°C).

What is the least humid month?

The least humid month is August, with an average relative humidity of 76%.

What month is the ocean warmest?

With an average ocean temperature of 85.5°F (29.7°C), August is the month with the warmest seawater.

What is the rainiest month?

September is the month with the most rainfall. Rain falls for 28.1 days and accumulates 10.28" (261mm) of precipitation.

What is the month with the lowest UV index?

September is the month with the lowest UV index, with an average maximum UV index of 6.

What is the month with the least sunshine in Hagåtña?

November has the least sunshine of the year, with an average of 6.3h of sunshine.

What is the month with the shortest days?

With an average of 11h and 18min of daylight, December has the shortest days of the year.

Is there Daylight Saving Time (DST)?

Hagåtña does not utilize Daylight Saving Time (DST). ChST timezone is used throughout the entire year.

Average temperature
Hagåtña, GU

Average temperature - Hagåtña, GU

The warmest months (with the highest average high temperature) are July and August (84.7°F).
The month with the lowest average high temperature is February (81.7°F).

The month with the highest average low temperature is June (83.3°F).
The coldest month (with the lowest average low temperature) is February (79.7°F).

Average pressure
Hagåtña, GU

Average pressure - Hagåtña, GU

The month with the highest atmospheric pressure is February (29.88"Hg).
The months with the lowest atmospheric pressure are August, September and October (29.79"Hg).

Average wind speed
Hagåtña, GU

Average wind speed - Hagåtña, GU

The windiest month (with the highest average wind speed) is February (16.3mph).
The calmest month (with the lowest average wind speed) is August (9.6mph).

Average humidity
Hagåtña, GU

Average humidity - Hagåtña, GU

The months with the highest relative humidity are January, March, April, May, October, November and December (78%).
The month with the lowest relative humidity is August (76%).

Average rainfall
Hagåtña, GU

Average rainfall - Hagåtña, GU

The wettest month (with the highest rainfall) is September (10.28").
The driest month (with the least rainfall) is March (1.81").

Average rainfall days
Hagåtña, GU

Average rainfall days - Hagåtña, GU

The months with the highest number of rainy days are July and August (28.9 days).
The month with the least rainy days is February (17.5 days).

Average sea temperature
Hagåtña, GU

Average sea temperature - Hagåtña, GU

The best month for swimming (with the highest average sea temperature) is August (85.4°F).
The coldest month (with the lowest average sea temperature) is February (82°F).

Average daylight / Average sunshine
Hagåtña, GU

Average daylight / Average sunshine - Hagåtña, GU

The month with the longest days is June (Average daylight: 12h and 54min).
The month with the shortest days is December (Average daylight: 11h and 18min).

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is November (Average sunshine: 6h and 18min).

Average sunshine days
Hagåtña, GU

Average sunshine days - Hagåtña, GU

The month with the most sunshine days is March (6.6 days).
The month with the least sunshine days is September (1.1 days).

Average UV index
Hagåtña, GU

Average UV index - Hagåtña, GU

The months with the highest UV index are January, February, March, April, May, June, July, August, October, November and December (UV index 7).
The month with the lowest UV index is September (UV index 6).

Average cloud cover
Hagåtña, GU

Average cloud cover - Hagåtña, GU

The months with the most cloud cover are January, August and October (Cloud cover 46).
The months with the least cloud cover are May and June (Cloud cover 39).

Average visibility
Hagåtña, GU

Average visibility - Hagåtña, GU

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Hagåtña, Guam, USA

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