December weather forecast
Thornleigh, Australia

December

Weather in December

December, the first month of the summer in Thornleigh, is still a warm month, with temperature in the range of an average low of 17.1°C (62.8°F) and an average high of 27.7°C (81.9°F).

Temperature

The advent of December brings an average high-temperature of a still warm 27.7°C (81.9°F), almost identical to the preceding month. An average low-temperature of 17.1°C (62.8°F) is recorded during the nights in December in Thornleigh.

Heat index

During December, the heat index is calculated to be a hot 30°C (86°F). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
Consider that heat index readings are for situations in the shade and light wind. An exposure to direct sunlight may lift the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is a numerical representation of warmth when taking temperature and moisture levels into account. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Considering the impact of direct sunlight, it's possible for the heat index to surge by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. In general, younger individuals are at greater risk than adults because they tend to sweat less. Also, having a larger skin surface to body size ratio and greater heat production due to their active behavior contribute to this danger.

Humidity

In Thornleigh, the average relative humidity in December is 68%.

Rainfall

In Thornleigh, during December, the rain falls for 14 days and regularly aggregates up to 36mm (1.42") of precipitation. Throughout the year, there are 149.1 rainfall days, and 546mm (21.5") of precipitation is accumulated.

Daylight

With an average of 14h and 24min of daylight, December has the longest days of the year in Thornleigh.
On the first day of December in Thornleigh, 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

November and December, with an average of 9.4h of sunshine, are months with the most sunshine.

UV index

January, February, November and December, with an average maximum UV index of 6, are months with the highest UV index in Thornleigh. A UV Index value of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: In December, the UV index of 6 transforms into the following advice:
Guard against overexposure. Protection from sun-induced harm is essential. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total sun protection. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.

Frequently asked questions

What are December temperatures in Thornleigh?
An average high-temperature, in December, in Thornleigh, is 27.7°C (81.9°F) and the average low-temperature is 17.1°C (62.8°F). In December, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which represents the influence of relative humidity on air temperature, is calculated to be 30°C (86°F).
What is the average humidity in December in Thornleigh?
The average relative humidity in December in Thornleigh is 68%.
How many days does it rain in December in Thornleigh?
In December, in Thornleigh, Australia, the rain falls for 14 days. Throughout December, 36mm (1.42") of precipitation is accumulated.
When are the longest days in Thornleigh?
December has the longest days of the year, with an average of 14h and 24min of daylight.
What is the average length of the day in December in Thornleigh?
The average day length in December in Thornleigh is 14h and 21min.
When are sunrise and sunset in December in Thornleigh?
In December, on the first day of the month, sunrise is at 5:37 am and sunset at 7:51 pm. On the last day of the month, in Thornleigh, Australia, sunrise is at 5:47 am and sunset at 8:09 pm AEDT.
What are the months with the most sunshine in Thornleigh?
The months with the most sunshine in Thornleigh are November and December, with an average of 9.4h of sunshine.
How long on average sun shines in December in Thornleigh?
The average sunshine duration in December is 9.4h.
What is the month with the highest UV index in Thornleigh?
January, February, November and December, with an average maximum UV index of 6, are months with the highest UV index.
What is the UV index intensity in December in Thornleigh?
In December, the average daily maximum UV index in Thornleigh is 6. A UV Index estimate of 6 to 7 represents a high hazard to health from unsafe exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility
Average temperature in December - Thornleigh, Australia
Average temperature in December
Thornleigh, Australia
  • Average high temperature in December: 27.7°C

The warmest month (with the highest average high temperature) is January (29.2°C).
The month with the lowest average high temperature is June (16.8°C).

  • Average low temperature in December: 17.1°C

The month with the highest average low temperature is January (18.8°C).
The coldest month (with the lowest average low temperature) is July (8.1°C).

Average pressure in December - Thornleigh, Australia
Average pressure in December
Thornleigh, Australia
  • Average pressure in December: 1013.3mbar

The month with the highest atmospheric pressure is June (1021mbar).
The month with the lowest atmospheric pressure is January (1012.9mbar).

Average wind speed in December - Thornleigh, Australia
Average wind speed in December
Thornleigh, Australia
  • Average wind speed in December: 10.2km/h

The windiest month (with the highest average wind speed) is December (10.2km/h).
The calmest month (with the lowest average wind speed) is April (8.8km/h).

Average humidity in December - Thornleigh, Australia
Average humidity in December
Thornleigh, Australia
  • Average humidity in December: 68%

The month with the highest relative humidity is June (76%).
The month with the lowest relative humidity is September (65%).

Average rainfall in December - Thornleigh, Australia
Average rainfall in December
Thornleigh, Australia
  • Average rainfall in December: 36mm

The wettest month (with the highest rainfall) is February (87mm).
The driest month (with the least rainfall) is May (27mm).

Average rainfall days in December - Thornleigh, Australia
Average rainfall days in December
Thornleigh, Australia
  • Average rainfall days in December: 14 days

The month with the highest number of rainy days is March (17.6 days).
The month with the least rainy days is August (7.9 days).

Average daylight in December / Average sunshine in December - Thornleigh, Australia
Average daylight in December /
Average sunshine in December
Thornleigh, Australia
  • Average daylight in December: 14h and 2min

The month with the longest days is December (Average daylight: 14h and 24min).
The month with the shortest days is June (Average daylight: 10h and 0min).

  • Average sunshine in December: 9h and 2min

The months with the most sunshine are November and December (Average sunshine: 9h and 24min).
The month with the least sunshine is June (Average sunshine: 5h and 48min).

Average sunshine days in December - Thornleigh, Australia
Average sunshine days in December
Thornleigh, Australia
  • Average sunshine days in December: 14.2 days

The month with the most sunshine days is August (21 days).
The month with the least sunshine days is February (10.4 days).

Average UV index in December - Thornleigh, Australia
Average UV index in December
Thornleigh, Australia
  • Average UV index in December: 6

The months with the highest UV index are January, February, November and December (UV index 6).
The months with the lowest UV index are May, June, July, August and September (UV index 4).

Average cloud cover in December - Thornleigh, Australia
Average cloud cover in December
Thornleigh, Australia
  • Average cloud cover in December: 40

The month with the most cloud cover is February (Cloud cover 46).
The month with the least cloud cover is August (Cloud cover 25).

Average visibility in December - Thornleigh, Australia
Average visibility in December
Thornleigh, Australia
  • Average visibility in December: 9km

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).

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