Guam Temperature by Month

Guam in Micronesia enjoys a stable climate, with daytime temperatures staying close to 29°C (84°F) throughout the year. Explore the full monthly breakdown below.

In Guam temperatures are generally consistent throughout the year. Maximum daytime temperatures range from a comfortable 28°C (82°F) in February to a comfortable 30°C (86°F) in June. Nighttime lows range from 27°C (81°F) in June to 26°C (79°F) in February.

The chart below illustrates the average maximum day and minimum night temperatures in Guam by month:

The coldest point of the day usually falls between 4 AM and 6 AM, with temperatures peaking around 3 PM. June, the city's warmest month, gets 196 hours of sunshine.

The chart below shows the average temperature throughout the year:

Guam's average annual maximum temperature is 29°C (84°F). To put that in context, here's how it compares to a few well-known destinations:

Rome, Italy averages 20°C (68°F) annually, with reliably warm summers and comfortable winters.

On the cooler end, Oslo, Norway averages just 10°C (50°F) annually, with pleasant summers but long, cold winters.

San Francisco, USA averages 19°C (66°F) annually, but with little seasonal variation, summers are often cool and foggy, winters mild.

Melbourne, Australia averages 20°C (68°F) annually, known for unpredictable weather, with four seasons sometimes happening in one day.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained, so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.

For more on Guam's weather, including monthly rainfall, sunshine hours, and humidity, visit our Guam climate page.