December weather forecastSydney, Australia

Weather in December

December announces the arrival of summer in Sydney, marking an annual peak in temperatures and humidity. The city is buzzing with visitors eager to experience Christmas festivities under the southern hemisphere's radiant sun. The longest daylight period is found in December, spanning across a generous 14.4 hours. As the mercury rises, more individuals are drawn towards the beckoning waters of Sydney's famous beaches. Overwhelmingly, December stands as a celebratory period with weather conditions perfect for end-of-year festivities.

Temperature

Sydney, Australia, starts December with an average high-temperature of a still warm 25.2°C (77.4°F), hinting at a minimal fluctuation from November. During the month of December, Sydney experiences a steady low-temperature average of 17.5°C (63.5°F).

Humidity

In Sydney, Australia, the average relative humidity in December is 59%.

Rainfall

In Sydney, Australia, during December, the rain falls for 11.5 days and regularly aggregates up to 78mm (3.07") of precipitation. Throughout the year, there are 143.4 rainfall days, and 1212mm (47.72") of precipitation is accumulated.

Sea temperature

In December, the average sea temperature in Sydney is 21.9°C (71.4°F).
Note: When the surface water temperature is 21.9°C (71.4°F), most do not enjoy swimming. Breathing control becomes more complex as temperatures drop below 21°C (69.8°F).

Daylight

The month with the longest days in Sydney is December, with an average of 14h and 24min of daylight.
On the first day of December in Sydney, Australia, sunrise is at 5:37 am and sunset at 7:51 pm. On the last day of the month, sunrise is at 5:47 am and sunset at 8:09 pm AEDT.

Sunshine

The months with the most sunshine in Sydney are August through October and December, with an average of 7.9h of sunshine.

UV index

The months with the highest UV index in Sydney are January and December, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an excessive health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The UV index of 12 during December translates into the following guidance:
Take all critical precautions, unprotected skin might burn swiftly. The hours from 10 a.m. to 4 p.m. have the most intense UV radiation. As much as possible, limit direct sun exposure during this period. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Maintain skin health by using sunscreen with a minimum of 30 SPF. This keeps you safe from sunburn and the Sun's harmful radiation. Alert! The Sun's UV rays are heightened by the reflection of sand and water.