December weather forecast
Petaling Jaya, Malaysia

December gets a head start on lowering temperatures in advance of the approaching new year, reaching a high of 30.9°C (87.6°F) and a low of 23.3°C (73.9°F). Although it marks an increase in rainfall to 153mm (6.02"), pressure averages out at 1009.6mb, suggesting relatively stable weather conditions. Despite frequent showers, the charm of Petaling Jaya is radiant in the satisfactory daylight. As the city moves towards January, temperatures are expected to remain lower while pressure and humidity levels increase slightly, offering a cool start to January.

Temperature

With average temperatures fluctuating between a high of 30.9°C (87.6°F) and a low of 23.3°C (73.9°F), December stands out as the coldest month in Petaling Jaya, Malaysia.

Heat index

For December, the heat index is calculated to be a scorching 41°C (105.8°F). Implement additional safety measures to avoid heat cramps and heat exhaustion. Persistent activity might trigger heatstroke.
When considering the heat index, it's pivotal to note it is for shade and mild wind conditions. Heat index values can rise by 15 Fahrenheit (8 Celsius) degrees when in direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is a calculation that merges air temperature and relative humidity to depict the sensation of warmth. The perception of temperature can be subjective, varying based on activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. Being under direct sunshine can magnify the heat experience, possibly pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Younglings are generally more in peril than adults due to their reduced perspiration. Coupled with a larger skin surface relative to their tiny bodies and greater heat production because of their activity, they become more at risk.
Sweat evaporation, driven by perspiration, is the method the human body uses to rid itself of excessive warmth. With excessive moisture in the atmosphere, the effectiveness of the evaporation process is decreased, causing the body to cool down less efficiently, leading to a sensation of overheating. Inadequate heat shedding in the face of rising body temperatures hints at potential dehydration risks.

Humidity

December is the most humid month, with an average relative humidity of 82%.

Rainfall

In Petaling Jaya, during December, the rain falls for 26.8 days and regularly aggregates up to 153mm (6.02") of precipitation. In Petaling Jaya, during the entire year, the rain falls for 309.8 days and collects up to 1481mm (58.31") of precipitation.

Daylight

With an average of 11h and 54min of daylight, December has the shortest days of the year in Petaling Jaya.
On the first day of the month, sunrise is at 7:04 am and sunset at 7:01 pm. On the last day of December, sunrise is at 7:18 am and sunset at 7:15 pm +08.

Sunshine

November and December, with an average of 7.4h of sunshine, are months with the least sunshine.

UV index

The months with the highest UV index are February through October and December, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: In December, the maximum UV index of 7 suggests this advice:
Persist with precautions and heed sun safety advice. Prevention of sunburn is compulsory. The Sun emits the most powerful UV radiation between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.