January weather forecast
Naha, Japan

In Naha, Japan, January marks the beginning of the year with moderate temperatures and noticeable humidity. The temperatures range from 14.6°C (58.3°F) to 19.5°C (67.1°F) readily inviting a moderate climate suitable for light clothing. Weather conditions tend to be slightly unstable, with bouts of rain frequently interrupting periods of sunshine. This month experiences relatively long daylight, favoring outdoor activities. Prepare for a balmy sea temperature if beach activities are on the schedule.

Temperature

Naha's coldest temperatures are experienced in January, with average high temperatures of 19.5°C (67.1°F) and lows of 14.6°C (58.3°F).

Humidity

In Naha, the average relative humidity in January is 67%.

Rainfall

In January, in Naha, the rain falls for 12.9 days. Throughout January, 107mm (4.21") of precipitation is accumulated. Throughout the year, in Naha, there are 140.8 rainfall days, and 2037mm (80.2") of precipitation is accumulated.

Sea temperature

In Naha, Japan, the average seawater temperature in January is 22.3°C (72.1°F).
Note: Considering one's resistance to cold, elements like sunshine, wind, and the prevailing temperature matter when taking a swim in 22.3°C (72.1°F) waters. (For comparison, the Olympic swimming standard is set between 25°C (77°F) and 28°C (82.4°F).)

Daylight

The average length of the day in January is 10h and 43min.
On the first day of the month, sunrise is at 07:16 and sunset at 17:48. On the last day of January, in Naha, sunrise is at 07:14 and sunset at 18:10 JST.

Sunshine

The month with the least sunshine in Naha, Japan, is January, with an average of 3h of sunshine.

UV index

In January, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for the average person.
Note: The daily high UV index of 6 in January translates into this advice:
Persist with safeguards and heed sun safety doctrines. Keeping sunburn at bay is of prime importance. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Take note! The UV strength of the Sun elevates when reflected off water and sand.