Guam weather in August 2025

Expect 31°C daytime maximum temperatures in the shade with on average 5 hours of sunshine per day in Guam in August. Check more long-term weather averages for Guam in August before you book your next holiday to Guam in 2025/2026.

  • 31°C maximum daytime temperature in August in Guam (Agana)31
    31°C max day temperature
  • 5 hours of sunshine per day
  • 20 days with some rainfall in August in Guam (Agana)20
    20 days with some rainfall
  • 25°C minimum night-time temperature in August in Guam (Agana)25
    25°C min night temperature
  • 13 hours of daylight per day in August in Guam (Agana)13
    13 hours of daylight per day
  • Very high heat & humidity in August in Guam (Agana)VH
    Very High heat & humidity
  • 363 mm monthly rainfall in August in Guam (Agana)363
    363 mm of monthly rainfall
  • UV (maximum) index 11+ (Extreme) in August in Guam (Agana)11
    11+ (Extreme) UV index
  • 29°C sea temperature in August in Guam (Agana)29
    29°C sea temperature

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The August weather guide for Guam, represented by Agana, (Agana) shows long term 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.

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

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How hot is it in Guam in August?

Daytime temperatures usually reach 31°C in Agana, Guam in August with very high heat and humidity, falling to 25°C at night.

How sunny is it in Guam in August?

There are normally 5 hours of bright sunshine each day in Agana, Guam in August - that's 37% of daylight hours.

How warm is the sea around Guam in August?

The average sea temperature around Agana, Guam in August is 29°C.

Does it rain in Guam in August?

There are usually 20 days with some rain in Agana, Guam in August and the average monthly rainfall is 363mm.

What is the chance of a typhoon in Guam in August?

On average 2.2 days in August in Agana, Guam are likely to be affected by the passage of one or more tropical storms.

Guam August sunrise & sunset times

Browse the sunrise and sunset times for Guam in August 2025. Select a month to view Guam sunrise and sunset times for the next 12 months. The Guam sunrise and sunset times shown below are for Agana.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Friday, 1st August 2025 06:06 18:49
Saturday, 16th August 2025 06:08 18:42
Sunday, 31st August 2025 06:10 18:33

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