Hagatna weather by month
Hagatna runs from about 26°C in February to 28°C in December, with September the wettest month at 573 mm.
warmest month
December
28°C
coolest month
February
26°C
wettest month
September
573 mm
worst air month
April
8 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 27°C | 47 mm | 320 h | 6 |
| February | 26°C | 36 mm | 305 h | 7 |
| March | 27°C | 43 mm | 343 h | 5 |
| April | 28°C | 72 mm | 356 h | 8 |
| May | 28°C | 86 mm | 382 h | 8 |
| June | 28°C | 121 mm | 362 h | 5 |
| July | 27°C | 355 mm | 317 h | 5 |
| August | 27°C | 303 mm | 298 h | 4 |
| September | 27°C | 573 mm | 251 h | 3 |
| October | 27°C | 466 mm | 243 h | 4 |
| November | 28°C | 192 mm | 286 h | 6 |
| December | 28°C | 77 mm | 321 h | 7 |
About 3,784 hours of sun a year. Roughly 188 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-24. Full method, licences and the list of sources we rejected are on the methodology page.