Sendai weather by month
Sendai runs from about 2°C in January to 26°C in August, with August the wettest month at 265 mm.
warmest month
August
26°C
coolest month
January
2°C
wettest month
August
265 mm
worst air month
March
14 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 2°C | 96 mm | 229 h | 8 |
| February | 3°C | 63 mm | 188 h | 12 |
| March | 4°C | 136 mm | 250 h | 14 |
| April | 13°C | 75 mm | 271 h | 11 |
| May | 17°C | 111 mm | 284 h | 11 |
| June | 20°C | 91 mm | 272 h | 11 |
| July | 25°C | 154 mm | 234 h | 13 |
| August | 26°C | 265 mm | 291 h | 12 |
| September | 23°C | 196 mm | 214 h | 9 |
| October | 17°C | 89 mm | 211 h | 10 |
| November | 9°C | 59 mm | 232 h | 10 |
| December | 3°C | 42 mm | 200 h | 8 |
About 2,876 hours of sun a year. Roughly 139 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 2026-05-23. Full method, licences and the list of sources we rejected are on the methodology page.