Nagasaki weather in January
In January, Nagasaki has daytime highs averaging 9.7 °C, nights around 6.1 °C, with 10 wet days, and a sea temperature of 17 °C. Figures are 1991–2020 climate normals.
- 9.7°C Average high
- 6.1°C Average low
- 10days Wet days
- 80mm Rainfall
- 16.7°C Sea temperature
- 10h Daylight
Daily temperatures through January
How January develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 January | 10.3 °C | 6.6 °C | 28 % |
| 11–20 January | 9.6 °C | 6.1 °C | 34 % |
| 21–31 January | 9.3 °C | 5.5 °C | 36 % |
- Rain is most likely over days 21–31 of January (36 % of days) and least likely over days 1–10 (28 %).
What to expect
| Measure | Typical January | Share of the month |
|---|---|---|
| Days above 25 °C | 0 of 31 | 0 % |
| Days above 30 °C | 0 of 31 | 0 % |
| Days below 0 °C | 0.2 of 31 | 1 % |
| Days with more than 1 mm rain | 10 of 31 | 33 % |
Conditions in January
| Measure | Average |
|---|---|
| Mean temperature | 7.9 °C |
| Record high (1991–2020) | 19 °C |
| Record low (1991–2020) | -1.4 °C |
| Relative humidity | 67 % |
| Wind speed | 24 km/h |
| Cloud cover | 68 % |
January compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 9.7 °C | 80 mm | 68 % |
| February | 10.6 °C | 99 mm | 64 % |
| March | 13.5 °C | 149 mm | 62 % |
| November | 17.1 °C | 105 mm | 52 % |
| December | 11.9 °C | 90 mm | 61 % |
See all twelve months for Nagasaki
- January is the 12th warmest month here.
- It is the 1st driest month of the year.
- It ranks 10th for least cloud cover.
- Days last about 10 hours from sunrise to sunset.
- It rains on 10 of 31 days — 33 % of the month.
- Nights are about 3.6 °C cooler than the middle of the day.
- The hottest January day on record since 1991 reached 19 °C, 8.9 °C above the usual daytime high.
QuestionsJanuary in Nagasaki, answered
How warm is Nagasaki in January?
Daily highs average 9.7 °C and nights fall to about 6.1 °C, a spread of 3.6 °C between afternoon and dawn. That makes January the 12th warmest month of the year here.
Does it rain much in Nagasaki in January?
January averages 80 mm of rain, spread over about 10 of the 31 days — 33 % of the month. Cloud cover averages 68 % of the sky.
Is the sea warm enough to swim in January?
The sea averages 17 °C off Nagasaki in January. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in January?
Nagasaki averages 10 hours between sunrise and sunset in January. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.