December weather forecast
Johannesburg, South Africa

December welcomes summer in Johannesburg, accompanied by a further rise in temperatures and continued high precipitation of 105mm (4.13"). The sun blazes down, with the UV index hitting the top of the scale. The heightened humidity offers a tropical charm to the city's appeal, while the extended daylight hours maximize time for outdoor activities. Despite the high rainfall, the South African city of Johannesburg enjoys abundant sunlit hours, making December a popular month for tourists and locals alike to revel in the vibrant summer festivities.

Temperature

The shift into December finds Johannesburg at an average high-temperature of a still moderately hot 25.2°C (77.4°F), closely comparable to November's conditions. Nighttime temperatures in Johannesburg hover around an average low of 13.9°C (57°F) in December.

Humidity

The average relative humidity in December is 66%.

Rainfall

In Johannesburg, in December, it is raining for 14.9 days, with typically 105mm (4.13") of accumulated precipitation. Throughout the year, there are 99.3 rainfall days, and 713mm (28.07") of precipitation is accumulated.

Daylight

The month with the longest days is December, with an average of 13h and 48min of daylight.
On the first day of the month, sunrise is at 05:07 and sunset at 18:46. On the last day of December, sunrise is at 05:18 and sunset at 19:03 SAST.

Sunshine

In December, the average sunshine is 8.5h.

UV index

The months with the highest UV index are January through March, November and December, with an average maximum UV index of 12. A UV Index reading of 11, and higher, represents an ultimate health vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: An average UV index of 12 in December transforms into this advice:
Enforce every vital precaution. Those with light skin could endure burns in a matter of minutes. The Sun's UV radiation is most potent between 10 a.m. and 4 p.m. Try to limit direct exposure to the Sun during this period. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.