Guam has an average annual temperature of
82°F
(across all 3 cities) with approximately
1473 mm of annual precipitation
and average humidity of 80%.
The warmest city is Agat
with average July highs of 85.3°F,
while Hagatna
is the coldest with average January lows of 79°F.
This page covers 45 years of NASA POWER climate data (1981–2025)
including temperature, rainfall, humidity, wind speed, and solar radiation.
Oct is typically the warmest month across Guam with average highs around
85.1°F, while
Mar is the coldest with average lows near
78.6°F.
Aug is the wettest month with approximately
276 mm of rainfall on average.
Month
Max Temp
Min Temp
Avg Temp
Rain (mm)
Humidity
Wind (m/s)
Solar (kWh/m²)
Jan
83.1°F
79°F
81.1°F
74
78%
6.5
4.90
Feb
82.6°F
78.6°F
80.6°F
48
78%
6.5
5.40
Mar
82.8°F
78.6°F
80.8°F
37
78%
6.2
6.20
Apr
83.8°F
79.5°F
81.7°F
45
79%
5.8
6.70
May
84.9°F
80.6°F
82.8°F
56
80%
5.1
6.60
Jun
85.1°F
80.8°F
82.9°F
93
80%
4.7
6.30
Jul
85.1°F
80.4°F
82.8°F
192
82%
4.2
5.60
Aug
85.1°F
80.2°F
82.8°F
276
82%
4.2
5.20
Sep
85.1°F
80.2°F
82.8°F
252
82%
4.1
5.10
Oct
85.1°F
80.4°F
82.8°F
211
82%
4.6
5.00
Nov
84.9°F
81.1°F
83.1°F
135
81%
6.0
5.00
Dec
84.2°F
80.2°F
82.2°F
81
79%
6.5
4.80
📈 Guam Yearly Climate Trends
🌡️ Annual Temperature Trend
State-wide avg annual high & low · Last 10 years
📈 Guam Long-Term Climate Trends (1981–2025)
This chart shows how Guam's average temperatures have shifted across 45 years.
Use the range buttons to focus on recent decades or view the full historical record.
Data is averaged across all 3 cities in the state.
🌧️ Annual Precipitation Trend
State-wide avg annual precipitation · Last 10 years · mm/year
🔗 Explore Cities in Guam
Browse detailed weather history, monthly averages, and 45-year climate trends for every city in Guam.
Agat is the wettest city in Guam with approximately 1486 mm of annual precipitation on average. View Agat weather history →
What is the warmest month in Guam?▼
Oct is the warmest month across Guam, with state-wide average highs of 85.1°F and average lows of 80.4°F.
How many cities in Guam have weather data?▼
TownPillar has historical weather data for 3 cities in Guam, covering 45 years of NASA POWER climate records from 1981 to 2025.
Which month has the most sunshine in Guam?▼
Apr is the sunniest month across Guam with an average solar radiation of 6.70 kWh/m²/day state-wide. This solar radiation data from NASA POWER is useful for solar energy planning, agriculture, and understanding seasonal sunshine availability.
Where does this climate data come from?▼
All data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis data. It includes monthly temperature, precipitation, humidity, wind speed, and solar radiation at 0.5° × 0.625° spatial resolution.
📚 Data Source
All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources). Data covers 45 years (1981–2025) across 3 cities in Guam at monthly temporal resolution.