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
💧 Humidity peaks at 82% in August · annual avg 80%
Monthly averages · 1981–2025
Across 45 years, Guam's temperature has remained relatively stable over the past decade. 2025 was the warmest year overall and 1993 the coolest.
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 30 years · °F
Averaged across all 3 cities in Guam · Last 30 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.
