Osaka weather by month
Osaka runs from about 5°C in January to 30°C in August, with June the wettest month at 374 mm.
warmest month
August
30°C
coolest month
January
5°C
wettest month
June
374 mm
worst air month
February
25 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 5°C | 40 mm | 229 h | 16 |
| February | 7°C | 132 mm | 200 h | 25 |
| March | 8°C | 159 mm | 241 h | 21 |
| April | 16°C | 169 mm | 228 h | 21 |
| May | 18°C | 276 mm | 277 h | 16 |
| June | 23°C | 374 mm | 263 h | 19 |
| July | 28°C | 246 mm | 317 h | 18 |
| August | 30°C | 188 mm | 338 h | 20 |
| September | 28°C | 90 mm | 302 h | 17 |
| October | 21°C | 182 mm | 224 h | 14 |
| November | 14°C | 126 mm | 235 h | 23 |
| December | 7°C | 4 mm | 270 h | 20 |
About 3,124 hours of sun a year. Roughly 192 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 2026-05-22. Full method, licences and the list of sources we rejected are on the methodology page.