Guide 09 · Seasonal comparison
Winter across Japan: January from Sapporo to Naha
January is the clearest month in this five-city set for showing why a city-level baseline matters. The data does not provide packing, safety or travel-disruption advice.
January climate normals
| Observatory | Mean °C | Daily high °C | Daily low °C | Precip. mm | Sun h |
|---|---|---|---|---|---|
| Sapporo | -3.2 | -0.4 | -6.4 | 108.4 | 90.4 |
| Tokyo | 5.4 | 9.8 | 1.2 | 59.7 | 192.6 |
| Osaka | 6.2 | 9.7 | 3.0 | 47.0 | 146.5 |
| Fukuoka | 6.9 | 10.2 | 3.9 | 74.4 | 104.1 |
| Naha | 17.3 | 19.8 | 14.9 | 101.6 | 93.1 |
One month, a wide range
The selected January mean temperatures range by 20.5°C between Sapporo and Naha. The table also complicates a simple temperature story: Tokyo has the highest January sunshine-duration normal in this five-city group, while the precipitation totals have a different order. A visitor should not infer daily weather from these totals, but can use them to compare the long-run profiles.
There is no single January condition for Japan. Keeping the observatory names and the 1991–2020 period visible makes the limitations as clear as the numerical contrast.
Source and limits. JMA Tables of Climatological Normals (1991–2020). These are not forecasts or safety guidance.