Weather in Guam in December 2025
Average weather
Average temperature in Guam in December
The temperature in December is +30°C on average, with a range between a maximum of +31°C during the day and a minimum of +25°C at night.
The average maximum temperature goes down 17% by the end of the month, compared with the beginning of the month, from +31°C to +30°C.
Is Guam warm or cold in December?
Guam is typically warm in December.
Maximum temperatures go up compared to the previous month from +29°C to +29°C. The minimum temperature also goes up from +26°C to +26°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
December is one of the warmest months in Guam, here is the comparison with other months:
Climate in Guam in December
| November | December | January | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +29°C | +29°C | +28°C | ||||
| Min. temperature | ||||||
| +23°C | +23°C | +22°C | ||||
| Max. temperature | ||||||
| +33°C | +32°C | +32°C | ||||
| Rainfall | ||||||
| 238 mm | 151 mm | 121 mm | ||||
| Wind | ||||||
| 4 m/s | 5 m/s | 5 m/s | ||||
| Humidity | ||||||
| 82% | 81% | 79% | ||||
| Air pressure | ||||||
| 1009 HPa | 1009 HPa | 1010 HPa | ||||
| Sunny days | ||||||
| 1 | 1 | 2 | ||||
| Cloudy days | ||||||
| 1 | 2 | 4 | ||||
| Rainy days | ||||||
| 28 | 28 | 25 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
December weather is still as ok as in November. The temperature levels stay the same in the area of +29°C for average maximum temperature during the day. As December arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 238 mm to 151 mm. It feels drier, as humidity decreases from 82% to 81%. Winds are stronger in comparison to November, going up from 4 m/s to 5 m/s on average. The amount of sunny days stay about the same, averaging 1 sunny days during the month.
January brings much the same weather, it remains ok.
Wind
The average wind speed is 6 m/s getting up to 8 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Guam is gradually increasing during December, going from 5 m/s to 6 m/s over the course of the month.
Rain
How was the weather last December in Guam?
Climate Change over Years
The climate in Guam in December has not changed much over the last 43 years.
The average temperature was the lowest in 1983 (+27°C) and the highest in 2018 (+31°C). The driest year was 1983 with only 1154 mm of rainfall, and the wettest year was 2023 with 4623 mm.
FAQ
Is December a good time to visit Guam?
Can you sunbathe in Guam in December?
Is Guam rainy in December?
Is it sunny in Guam in December?
Monthly weather in Guam
Source of the data
For this page, we’ve looked at the typical weather in Guam, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
