Nagasaki weather in December
Temperature, sea and sunshine in December: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in December
Fair
Best time to visit: April – May, September – November
What is the weather like in Nagasaki in December?
In December, Nagasaki is cool: daytime highs average 12 °C, and nights cool down to about 9 °C. The sea averages 18.7 °C – bracing, so a wetsuit helps for longer swims. The sun is scarce, with only about 4 hours a day. Rain is frequent, with about 11 rainy days and 88 mm in total. All in all, December is a so-so month for a holiday in Nagasaki.
December compared
How the weather changes from November to January. Tap a month to open it.
| NovemberNov | DecemberDec | JanuaryJan | |
|---|---|---|---|
| Score | 71 | 40 | 26 |
| Day | 18° | 12° | 10° |
| Night | 14° | 9° | 7° |
| Sea | 22° | 19° | 17° |
| Sun | 5 h | 4 h | 3 h |
| Rain days | 9 | 11 | 11 |
More details for December
- Daylight
- 10 h 1 min07:15 – 17:16
- UV index
- 3 · moderateclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 24 km/haverage daily peakAll months
- Cloud cover
- 60 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+9Asia/Tokyo
How the score comes together
- Temperatureweight 50 %43 %
- Sunshineweight 20 %12 %
- Few rainy daysweight 30 %54 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in December
- A jumper for the evenings
- Rain jacket or umbrella
Nagasaki in December: quick answers
Is Nagasaki hot in December?
No. In December, Nagasaki is cool: daytime highs average 12 °C and nights drop to about 9 °C.
Can you swim in Nagasaki in December?
Only if you don't mind cold water: in December the sea averages just 18.7 °C. Comfortable swimming is possible from June to November.
Does it rain much in Nagasaki in December?
Rain is frequent, with about 11 rainy days and 88 mm in total.
Nagasaki month by month
The whole year in NagasakiAll destinations: JapanWhere to go in DecemberSea temperature in December
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences