January weather forecast
Koloa, Tonga

Koloa, Tonga starts the year in January with high humidity and a significant amount of rainfall contributing to the wet season. January's heavy monsoon showers result in a total rainfall of 275mm (10.83"), the highest in the year. As the month progresses, it continues a similar pattern of weather witnessed in the rainy season. Sweltering highs and sticky nights dominate January, while the late afternoon often sees tropical thunderstorm activity. It's a month when protective rain gear, sunblock and insect repellents become weather essentials for locals and visitors alike.

Temperature

In January, Koloa notes an average high-temperature of a still moderately hot 27.8°C (82°F), hardly different from the preceding month. A minimal decline in temperature from daytime highs is anticipated throughout the January nights, averaging a still warm 27.2°C (81°F).

Heat index

The heat index value during January is calculated to be a hot 31°C (87.8°F). When exposure and activity are sustained, they could induce fatigue, with a chance of heat cramps.
Research indicates the heat index considers values in shaded locales and with light winds. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', binds temperature metrics with humidity values to give a sense of the actual warmth. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Kids are usually more vulnerable than adults, given their lesser sweating ability. Along with their larger skin surface relative to their small stature and the excess heat due to their activity, their risk is amplified.

Humidity

The average relative humidity in January is 78%.

Rainfall

January is the month with the most rainfall. Rain falls for 23 days and accumulates 275mm (10.83") of precipitation.

Daylight

In January, the average length of the day is 13h and 6min.
On the first day of the month, sunrise is at 06:02 and sunset at 19:16. On the last day of January, in Koloa, sunrise is at 06:21 and sunset at 19:17 +13.

Sunshine

In January, the average sunshine in Koloa is 7h.

UV index

The months with the highest UV index in Koloa, Tonga, are January through April and December, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for the average person.
Note: The daily high UV index of 7 in January translates into this advice:
Avoid overexposure. Fair-skinned individuals can burn in under 20 minutes. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.