Which is the hottest month in Guam?

The hottest time of year in Agana, Guam is normally September. Expect maximum daytime temperatures to reach 31°C with very high heat and humidity.

Best time to visit Guam

Q: When is the best time to visit Guam?

The best time to visit Guam (Agana) is March based on the following average weather conditions. Maximum daytime temperature = 22 - 30°C. Daily hours of sunshine = 10 hours or more.

Q: Which month has the most rain in Guam?

In terms of rainfall, August is usually the wettest month in Agana, Guam with 363mm on average. There are normally 20 days in August with some rain.

Q: When is it sunniest in Guam?

The sunniest time of year in Agana, Guam is normally March with bright sunshine on average for 58% of daylight hours; that's 7 hours of sunshine per day.

Q: When is the sea warmest in Guam?

The sea is usually at its warmest in Agana, Guam in August when the water temperature reaches 29°C.

Find the best time to visit Guam and plan your perfect trip in 2025/2026. Get holiday inspiration, weather guides, travel advice and find great deals.

Guam by month

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

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When is the best time to visit Guam?

The best time to visit Guam (Agana) is March based on the following average weather conditions.

Maximum daytime temperature = 22 - 30°C [remove]
Daily hours of sunshine = 10 hours or more [remove]

Change the criteria to reflect your weather preferences.

3
Jan
3
Feb
3.5
Mar
3
Apr
3
May
2.5
Jun
2
Jul
2
Aug
2
Sep
1.5
Oct
2
Nov
2.5
Dec

Change criteria

Max Day Temperature (°C)

30
Jan
30
Feb
30
Mar
31
Apr
31
May
31
Jun
31
Jul
31
Aug
31
Sep
31
Oct
31
Nov
30
Dec

Hours of Sunshine (daily)

6
Jan
6
Feb
7
Mar
7
Apr
7
May
7
Jun
5
Jul
5
Aug
5
Sep
4
Oct
5
Nov
5
Dec

Best time to visit

Destination

Daytime temperature

Sunshine hours

Sea temperature

Monthly rainfall

Days with some rain

Heat & humidity

The weather guide for Guam, represented by Agana, (Agana) shows long term weather averages processed from data supplied by CRU (University of East Anglia) & today's weather forecast provided by meteoblue. Find out more about our data sources.

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

More about Guam

Explore our complete guide to Guam with the latest travel advice for travellers and holidaymakers including official updates and local travel tips for Guam.

Essential travel guide
Travel guidance
Travel health
Travel features
Top travel deals
FAQs

Guam travel guide - essential info

Below is a beginner's guide to Guam with essential travel facts such as dominant language spoken, typical flight time from the UK and the local currency. You can also check whether visas are required and what plug adapter you need to pack.

Guam - quick facts
Time difference	UK +10 hours
Language(s)	English
Currency	US Dollar
Electricity	A + B plug (110V)
Driving side	Right
Visa^✝	Yes

Why visit Guam?

Considering a holiday to the Guam? Here are some of the very good reasons it makes such a wonderful holiday destination such as for its beaches to ensure you get the most out of your 2025/2026 escape.

Beaches

Guam tourist information

Guam Visitors Bureau

✝ = requirements for UK travellers.

Travelling to Guam?
Hotels Flights eSIMs

Guam travel guidance

Check the latest travel guidance and advice on visiting Guam from official government sources (in english) from around the world including entry requirements and travel restrictions.

Canadian travel advice for Guam - Government of Canada
Safe travel advisories for Guam - Ministry of Foreign Affairs, New Zealand
Smarter traveller advice for Guam - Department of Foreign Affairs, Australia

Learn more about the current safety and security risks from terrorism, natural disasters and more. Read about the local laws and customs to consider when travelling around Guam.

Note: UK FCDO - UK Foreign, Commonwealth & Development Office

Guam travel health

Find out more about staying safe when travelling to Guam with the latest guidance on required vaccinations and recommended medication to take with you.

Vaccines & medicines for Guam - CDC
Health & vaccinations for Guam - TravelHealthPro, NaTHNac
How to stay safe & healthy in Guam - Fit for Travel, Public Health Scotland

Check out the general travel tips for staying safe and healthy in Guam, risks of preventable diseases and what to pack.

Note: CDC - Centers for Disease Control and Prevention

Guam travel features

Do you want to learn more about Guam? Read our latest features covering travel tips and insider destination guides on where to go and what to do in Guam.

We don't currently have any travel features on Guam. Discover more about holiday destinations around the world with this selection of general travel articles.

Guam FAQs

Read our frequently asked questions about travelling to Guam including the current entry restrictions, driving side, electrical plugs used and much more.

Which month has the most rain in Guam?

In terms of rainfall, January is usually the wettest month in Agana, Guam with 0mm on average. There are normally no days in January with some rain.

When is it sunniest in Guam?

The sunniest time of year in Agana, Guam is normally January with bright sunshine on average for 0% of daylight hours; that's 0 hours of sunshine per day.

When is the sea warmest in Guam?

The sea is usually at its warmest in Agana, Guam in January when the water temperature reaches 0°C.

What is the time difference between Guam and the UK?

The time difference between Guam and the UK is UK time+10 hours.

What is the main language spoken in Guam?

The main language spoken in Guam is English.

Learn a language for Guam with Rosetta Stone^*, Busuu^* and Rocket Languages^*.

What is the currency in Guam?

The currency in Guam is the US Dollar (USD).

Which plugs are used in Guam?

Guam uses electrical plug type A + B (110 Volts).

Which side of the road do they drive on in Guam?

They drive on the right side of the road in Guam.

Do you need a visa for Guam?

Yes, UK passport holders do need a visa to enter Guam.

Check Guam visa requirements for all passport holders with VisaHQ^*.

Guam travel deals

Holidays to Guam

Expedia^*

Check out the latest deals, discount codes and special offers on holidays to Guam in 2025/2026. Pay low deposits and save with last minute holiday availability and free kids places.