January weather forecast
Jakarta, Indonesia

January in Jakarta, Indonesia, starts the year off with a mix of warm temperatures, abundant rainfall, and high humidity. In comparison to December, January sees a slight increase in both temperature and humidity. The sea temperature remains consistent at 28°C (82.4°F) making beach activities still enjoyable. The majority of days are reportedly overcast with recorded cloud coverage of 46%. Wind speed this month remains moderate with a recorded average speed of 12.4km/h (7.7mph), and gusts reaching as high as 16.7km/h (10.4mph).

Temperature

The coldest months in Jakarta are January and February, with an average high-temperature of 29.8°C (85.6°F).

Heat index

The heat index in January is calculated to be a fiery hot 35°C (95°F). Undertake special precautions, the probability of heat exhaustion and heat cramps is high. Prolonged activity may provoke heatstroke.
Research indicates the heat index considers values in shaded locales and with light winds. The heat index could experience an increase of 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', shows a temperature sensation when both heat and moisture conditions are combined. Additional elements including metabolic differences, the level of physical activity, and attire have a role in shaping the individual's temperature perception. One must note that being under the direct sun can escalate the heat's effects, with the heat index possibly rising by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
To offset high temperatures, the human body releases sweat which, upon evaporation, cools it down. When air moisture content is high, the cooling process through evaporation is not as efficient, leading to an ineffective body cooling process and a feeling of overheating. Elevated heat gain compared to the body's release capability poses risks of dehydration and potential overheating.

Humidity

In January, the average relative humidity in Jakarta is 73%.

Rainfall

In January, the rain falls for 24.8 days. Throughout January, 127mm (5") of precipitation is accumulated. In Jakarta, during the entire year, the rain falls for 252 days and collects up to 1150mm (45.28") of precipitation.

Sea temperature

The months with the coldest seawater are January and February, with an average sea temperature of 28°C (82.4°F).
Note: Engaging in swimming, diving, or other water activities is highly enjoyable in temperatures ranging from 25°C (77°F) to 29°C (84.2°F), without any unpleasant sensations for prolonged durations.

Daylight

In January, the average length of the day is 12h and 26min.
On the first day of the month, sunrise is at 05:41 and sunset at 18:10. On the last day of January, in Jakarta, sunrise is at 05:54 and sunset at 18:17 WIB.

Sunshine

The average sunshine in January in Jakarta is 9.4h.

UV index

The months with the highest UV index in Jakarta are January through December, with an average maximum UV index of 7. January through December, with an average maximum UV index of 7, are months with the lowest UV index in Jakarta. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for average individuals.
Note: An average UV index of 7 in January transforms into this advice:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. It's important to stay in the shade and limit exposure to the sun from 10 a.m. to 4 p.m., when UV radiation is most intense, although remember that shade structures may not provide full sun protection. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Be cautious! Sand and water surfaces make the Sun's UV rays more potent.