Onomichi weather by month
Onomichi runs from about 5°C in January to 29°C in August, with June the wettest month at 287 mm.
warmest month
August
29°C
coolest month
January
5°C
wettest month
June
287 mm
worst air month
April
17 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 5°C | 35 mm | 216 h | 11 |
| February | 7°C | 142 mm | 200 h | 14 |
| March | 8°C | 125 mm | 247 h | 17 |
| April | 16°C | 159 mm | 219 h | 17 |
| May | 17°C | 187 mm | 293 h | 14 |
| June | 22°C | 287 mm | 257 h | 14 |
| July | 27°C | 214 mm | 317 h | 17 |
| August | 29°C | 125 mm | 347 h | 17 |
| September | 27°C | 36 mm | 318 h | 9 |
| October | 20°C | 207 mm | 208 h | 8 |
| November | 13°C | 118 mm | 234 h | 11 |
| December | 6°C | 3 mm | 263 h | 10 |
About 3,119 hours of sun a year. Roughly 166 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 2026-05-27. Full method, licences and the list of sources we rejected are on the methodology page.