December Weather in Hornsby, Australia

Last updated: August 22, 2025

In December, the average temperature in Hornsby, Australia is a pleasant 22°C (72°F). Expect a temperature range with a minimum of 12°C (54°F) and soaring highs of 41°C (106°F). You'll experience an average humidity of 68% and roughly 76 mm (3.0 in) of precipitation over about 10 days.

December Temperature in Hornsby

In December in Hornsby, the average temperature is 22°C (72°F), with maximums reaching up to 41°C (106°F) and minimums dipping as low as 12°C (54°F). Travelers should be prepared for a warm climate and pack accordingly for both hot days and cooler evenings.

December Weather in Hornsby: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Hornsby, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hornsby, December typically has an average temperature of 22°C (72°F), with highs reaching up to 41°C (106°F) and lows dropping to around 12°C (54°F).

Data source: Temperature data for Hornsby generated using information from the Copernicus Climate Change Service.

December Precipitation in Hornsby

In Hornsby in December, the total precipitation amount is 76 mm (3.0 in) spread over a period of 10 days.

December Precipitation Trends in Hornsby

The chart displays monthly precipitation patterns in Hornsby, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Hornsby, December typically receives around 76 mm (3.0 inches) of precipitation spread over approximately 10 days.

Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

December Humidity in Hornsby

In Hornsby in December humidity is 68%. With an average temperature of 22°C (72°F), this humidity feels like a warm embrace, slightly stifling but still manageable for traveling, creating an atmosphere that encourages leisurely outdoor activities while prompting occasional breaks for refreshment.

December Average Humidity in Hornsby

This chart illustrates the average monthly humidity levels in Hornsby, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Hornsby is approximately 68%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Hornsby

In Hornsby in December, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in Hornsby, you can check here.

Maximum UV Index Levels in Hornsby for December

The chart shows the monthly maximum UV Index (UVI) for Hornsby in December, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In December, the maximum UV index in Hornsby typically reaches 14, which falls under the extreme exposure category.

Data source: Hornsby December UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How December Weather in Hornsby Compares to Other Months

Weather in Hornsby varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Hornsby, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Hornsby, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	24°C (76°F)	37 mm (1.5 inches)	65%	extreme
February Weather	23°C (74°F)	107 mm (4.2 inches)	69%	extreme
March Weather	21°C (70°F)	153 mm (6.0 inches)	72%	extreme
April Weather	18°C (65°F)	29 mm (1.1 inches)	75%	very high
May Weather	15°C (59°F)	42 mm (1.7 inches)	74%	moderate
June Weather	12°C (54°F)	44 mm (1.7 inches)	72%	moderate
July Weather	12°C (53°F)	40 mm (1.6 inches)	68%	moderate
August Weather	13°C (55°F)	34 mm (1.3 inches)	67%	high
September Weather	16°C (60°F)	36 mm (1.4 inches)	63%	very high
October Weather	18°C (65°F)	67 mm (2.6 inches)	55%	very high
November Weather	20°C (68°F)	77 mm (3.0 inches)	57%	extreme
December Weather	22°C (72°F)	76 mm (3.0 inches)	68%	extreme