Guam has a warm subtropical climate with warm summers and mild winters.
Guam has an average annual temperature of 82.2°F across all 3 cities, with approximately 1499 mm of annual precipitation and average humidity of 80%. Temperatures peak in October and drop to their lowest in March, while rainfall is highest during summer months.
The warmest city is Agat with average July highs of 85.3°F, while Hagatna is the coldest with average January lows of 79.0°F. Humidity remains high throughout the year creating warm and humid conditions. These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
| Month | 🌤️ | High | Low | Avg | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|
| January | 😎 | 83.1°F | 79.0°F | 81.1°F | 78% | 73 | 6.5 | 4.90 |
| February | 😎 | 82.6°F | 78.6°F | 80.6°F | 78% | 49 | 6.5 | 5.40 |
| March | 😎 | 82.8°F | 78.6°F | 80.8°F | 78% | 37 | 6.2 | 6.20 |
| April | 😎 | 83.8°F | 79.5°F | 81.7°F | 79% | 45 | 5.8 | 6.70 |
| May | 🥵 | 84.9°F | 80.6°F | 82.8°F | 80% | 56 | 5.1 | 6.60 |
| June | ⛅ | 85.1°F | 80.8°F | 82.9°F | 80% | 95 | 4.7 | 6.30 |
| July | 🌧️ | 85.1°F | 80.4°F | 82.8°F | 82% | 191 | 4.2 | 5.60 |
| August | 🌧️ | 85.1°F | 80.2°F | 82.6°F | 82% | 275 | 4.2 | 5.20 |
| September | 🌧️ | 85.1°F | 80.2°F | 82.6°F | 82% | 251 | 4.1 | 5.10 |
| October | 🌧️ | 85.1°F | 80.4°F | 82.8°F | 82% | 212 | 4.6 | 5.00 |
| November | ⛅ | 84.9°F | 81.1°F | 82.9°F | 81% | 135 | 6.0 | 5.00 |
| December | ⛅ | 84.2°F | 80.2°F | 82.2°F | 79% | 82 | 6.5 | 4.80 |
Showing average climate conditions across 45 years (1981–2025) · averaged across all 3 cities in Guam
🧥 Light layers are sufficient — this Mild Winter stays cool without prolonged hard freezes.
🌤️ Conditions are ideal for outdoor activities throughout the day in this Mild Summer.
☔ Heavy Rainfall expected — carry rain gear and plan outdoor activities around these months.
Region-wide monthly averages across 3 cities · 1981–2025 · °F
Temperatures rise steadily from spring, peak in October, and gradually decline through autumn into winter.
These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
Region-wide monthly rainfall · 1981–2025 · mm/month
Monthly averages · 1981–2025
💧 Humidity peaks at 82% in August · annual avg 80%
The warmest year on record was 2025 (avg: 83.1°F), while the coldest year was 1993 (avg: 81.0°F).
Averaged across all 3 cities in Guam · Last 10 years · °F
Averaged across all 3 cities in Guam · Last 10 years · mm/year
🔥 hottest · ❄️ coldest · 🌧️ wettest
ℹ️ Values are averages across all 3 cities in Guam for each year.
| Year | Min Temp | Avg Temp | Max Temp | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|
2025 | 81.1°F | 83.1°F | 85.1°F | 1617 | 80% | 4.9 m/s |
2024 🔥 | 81.0°F | 83.1°F | 85.3°F | 1375 | 80% | 5.3 m/s |
2023 | 81.0°F | 83.1°F | 85.1°F | 1773 | 81% | 5.3 m/s |
2022 | 80.6°F | 82.8°F | 84.9°F | 1472 | 80% | 4.8 m/s |
2021 | 81.0°F | 83.1°F | 85.1°F | 1538 | 79% | 4.6 m/s |
2020 | 80.4°F | 82.6°F | 84.7°F | 1023 | 80% | 5.2 m/s |
2019 | 80.4°F | 82.6°F | 84.6°F | 1468 | 80% | 5.2 m/s |
2018 | 80.2°F | 82.4°F | 84.6°F | 1648 | 81% | 5.3 m/s |
2017 | 80.8°F | 82.9°F | 85.1°F | 1385 | 80% | 4.9 m/s |
2016 | 80.4°F | 82.6°F | 84.7°F | 1352 | 79% | 5.2 m/s |
Showing 1 to 10 of 45 years
All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.
