Nikko weather by month
Nikko runs from about 2°C in January to 25°C in August, with August the wettest month at 335 mm.
warmest month
August
25°C
coolest month
January
2°C
wettest month
August
335 mm
worst air month
July
14 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 2°C | 88 mm | 246 h | 4 |
| February | 4°C | 87 mm | 209 h | 7 |
| March | 5°C | 202 mm | 256 h | 10 |
| April | 13°C | 137 mm | 235 h | 11 |
| May | 16°C | 191 mm | 262 h | 11 |
| June | 20°C | 193 mm | 266 h | 9 |
| July | 25°C | 172 mm | 241 h | 14 |
| August | 25°C | 335 mm | 293 h | 13 |
| September | 23°C | 194 mm | 239 h | 9 |
| October | 17°C | 169 mm | 198 h | 6 |
| November | 10°C | 103 mm | 232 h | 5 |
| December | 3°C | 36 mm | 267 h | 4 |
About 2,944 hours of sun a year. Roughly 187 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 2026-05-25. Full method, licences and the list of sources we rejected are on the methodology page.