Remote Islands and Antarctica in December 2020

Australia's Indian Ocean islands: some wet days

  • Both Christmas Island Aero and Cocos Island Airport recorded close to average rainfall for the month.
  • Christmas Island Aero recorded 74.4 mm on the 8th, its wettest day since March and wettest December day since 2017.
  • Mean daytime and night-time temperatures were close to average at both Christmas Island Aero and Cocos Island Airport.

Australia's Pacific Ocean islands: warm days and nights

  • December rainfall was slightly below average at Lord Howe Island Aero and Norfolk Island Aero.
  • Lord Howe Island Aero recorded 42.8 mm on the 8th during the passage of a low pressure trough, its highest daily total in December since 2017.
  • Both daytime and night-time temperatures were warmer than average at Lord Howe Island Aero and Norfolk Island Aero.
  • Temperatures were cooler than average near the middle of the month at both sites, but most days and nights had temperatures close to or warmer than average.

Australia's Antarctic and sub-Antarctic territories: cooler than average

  • Total wind run for December was above average at Mawson and Macquarie Island, but close to average at Davis and below average at Casey.
  • The total monthly wind run was the highest in December at Mawson since 2017, and highest in December at Macquarie Island since 1999.
  • The strongest wind gust recorded for the month was 150 km/h at Mawson on the 16th.
  • The mean maximum and mean minimum temperatures at Australia's Antarctic stations were cooler than average during December.
  • Davis had its lowest December mean daily maximum temperature since 1999.
  • Casey had its lowest December mean daily minimum temperature since 1999.
  • The cooler than average maxima and minima meant that both Davis and Casey had their lowest December mean temperature since 1999.
  • Rainfall at Macquarie Island was close to average, with regular falls during the month.
  • After a cool start to the month, Macquarie Island finished December with warmer than average days and nights.
  • The mean maximum and mean minimum temperatures at Macquarie Island were both warmer than average.

Further information

Media
(03) 9669 4057

Lowest December mean daily maximum temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
December
Davis 1.3 0.3 in 1999 2.5



Lowest December mean daily minimum temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
December
Casey -4.9 -5.4 in 1999 -3.7



Lowest December mean temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
December
Casey -2.3 -2.8 in 1999 -1.1
Davis -1.0 -2.1 in 1999 0.2



Summary statistics for December 2020
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Precipitation
(millimetres)
Mean for
December
2020
Diff
from
average
Highest for
December
2020
Mean for
December
2020
Diff
from
average
Lowest for
December
2020
Total for
December
2020
Average
for
December
Rank of
December
2020
Fraction of
December
average
Offshore Islands (district 200)
Christmas Island Aero 27.6 -0.2 29.4 10th 22.5 -0.1 19.8 21st 244.2 223.5 average 109%
Cocos Island Airport 29.2 -0.2 30.2 9th 24.8 +0.2 22.7 12th 102.8 117.3 average 88%
Lord Howe Island Aero 24.6 +0.5 27.0 22nd 20.1 +0.8 14.2 11th 76.8 100.0 average 77%
Norfolk Island Aero 23.9 +0.5 25.9 8th 18.6 +0.7 16.0 3rd 50.8 85.0 average 60%
Antarctica and Macquarie Island (district 300)
Casey 0.4 -1.1 2.9 26th -4.9 -1.2 -9.4 15th 5.2 13.0 low 40%
Davis 1.3 -1.2 5.7 26th -3.2 -1.1 -7.8 12th 2.4 1.9 high 126%
Macquarie Island 8.6 +0.6 10.9 27th 4.8 +0.5 1.5 4th 87.8 80.9 average 109%
Mawson 1.8 -0.3 5.7 29th -4.2 -0.9 -7.3 15th
Note: Precipitation values from Casey and Davis should be used with caution.

Daily maximum temperatures for December 2020
Offshore Islands (200)12345678910111213141516171819202122232425262728293031
Christmas Island Aero29.027.528.027.726.726.726.225.027.529.428.327.026.627.627.326.527.427.127.728.027.027.627.728.028.528.727.827.728.028.427.5
Cocos Island Airport29.329.529.429.529.429.730.029.930.229.729.229.328.729.329.927.428.329.029.129.329.329.028.228.529.628.529.329.929.728.828.3
Lord Howe Island Aero24.126.222.824.725.325.025.525.022.123.323.320.922.322.824.525.224.725.626.626.525.527.024.423.224.423.624.525.826.425.524.9
Norfolk Island Aero22.522.323.223.525.325.925.525.923.924.023.423.721.022.725.025.023.924.024.824.024.724.925.823.723.323.023.123.923.522.2
Antarctica and Macquarie Island (300)12345678910111213141516171819202122232425262728293031
Casey-1.5-0.8-0.2-1.0-0.20.40.70.00.91.4-0.80.1-0.3-0.90.7-0.30.81.60.80.0-0.7-0.10.2-0.31.32.9-0.11.40.62.42.7
Davis-0.4-0.60.71.21.01.23.20.00.1-0.5-2.5-0.51.10.71.31.51.40.61.11.50.80.12.01.82.75.73.43.14.02.13.3
Macquarie Island8.48.76.14.26.88.49.77.28.26.15.77.29.08.49.07.09.08.39.010.610.510.610.49.88.29.410.99.110.010.510.4
Mawson-2.80.41.10.7-0.21.52.51.01.32.12.01.80.71.00.31.55.22.42.10.32.20.40.94.12.41.13.44.25.73.81.5
Values are the maximum temperature, usually in the 24 hours from 9 am on the day indicated,
and typically occurred in the afternoon of that day.
Temperatures coloured according to their difference
from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C Grey outline marks highest
and lowest for the period

Daily minimum temperatures for December 2020
Offshore Islands (200)12345678910111213141516171819202122232425262728293031
Christmas Island Aero24.023.123.223.123.524.023.122.420.323.023.022.621.523.523.622.322.422.221.621.319.820.721.221.322.723.223.623.023.222.722.4
Cocos Island Airport26.023.823.926.126.226.025.224.925.025.623.822.722.923.625.423.524.124.924.925.425.226.024.524.525.424.624.625.226.324.824.4
Lord Howe Island Aero18.420.519.520.222.121.822.819.618.615.014.219.019.420.120.621.421.421.521.721.622.821.920.218.418.418.519.720.920.222.721.2
Norfolk Island Aero18.016.516.016.417.920.420.921.422.618.517.017.119.019.519.619.519.219.018.318.618.917.417.720.318.217.916.416.918.319.5
Antarctica and Macquarie Island (300)12345678910111213141516171819202122232425262728293031
Casey-6.5-5.1-7.1-4.6-4.4-3.9-3.7-5.6-5.7-6.3-2.8-3.3-3.7-4.6-9.4-6.8-7.4-6.7-5.5-4.0-7.8-7.7-6.8-6.5-3.7-2.3-2.0-2.8-2.4-2.0-1.4
Davis-4.7-3.3-3.9-6.1-5.4-4.3-2.2-2.8-4.6-4.6-4.9-7.8-5.5-3.5-3.7-2.5-1.5-2.2-2.2-2.4-1.8-2.4-2.9-0.9-4.5-2.1-0.20.4-2.0-2.2-3.4
Macquarie Island3.56.92.81.52.12.45.84.83.51.81.63.24.46.27.32.55.36.05.55.26.86.37.25.32.03.27.68.45.67.05.7
Mawson-5.9-5.0-4.0-2.3-5.4-5.2-5.5-6.1-6.3-6.5-5.6-3.4-5.4-4.1-7.3-5.5-4.7-4.4-5.2-4.3-2.7-3.4-3.1-2.6-4.8-3.0-2.8-1.50.3-1.4-2.9
Values are the minimum temperature, usually in the 24 hours to 9 am on the day indicated,
and typically occurred that morning.
Temperatures coloured according to their difference
from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C Grey outline marks highest
and lowest for the period

Daily precipitation for December 2020
Offshore Islands (200)12345678910111213141516171819202122232425262728293031
Christmas Island Aero - 11.4 32.0 16.6 19.8 1.8 12.4 74.4 54.2 0.2 2.2 - - - 0.6 2.8 0.2 4.8 0.2 - - 0.2 - - - - 1.6 - - 8.8
Cocos Island Airport - 0.4 2.4 - - - - - - - 0.6 2.0 1.6 - - 22.8 0.4 - - - - - 0.2 25.2 0.4 19.4 10.2 - - 4.4 12.8
Lord Howe Island (Milky Way) 5.0 - 0.6 0.4 - - 1.6 46.4 6.4 - - - - - - - - 1.6 1.2 - - 0.6 6.8 0.6 - 6.2 0.2 0.2 6.4 - 0.2
Lord Howe Island Aero 3.0 - 2.0 0.4 0.2 - 1.8 42.8 6.2 - - 0.4 - - - - - 0.2 - - - 0.6 7.6 1.2 - 1.6 0.2 - 8.6 - -
Norfolk Island Aero 1.0 0.2 - - - - - - 0.6 16.4 - 27.6 0.4 - - - - - - - - - - 4.6
- - - - - -
Antarctica and Macquarie Island (300)12345678910111213141516171819202122232425262728293031
Casey - - - - - - - - - - 0.6 0.2 3.8 - - - - - - - - -
- 0.2 0.2 - 0.2 - - -
Davis - - - - - - - 2.2 - - - 0.2 - - - - -
- - - - - - - - - - - - -
Macquarie Island 5.8 14.4 5.0 1.4 - - 11.0 4.6 1.4 3.0 4.0 1.8 0.4 0.6 7.6 1.0 0.4 3.4 1.6 0.6 - - - 1.8 6.4 0.6 - - 8.6 1.6 0.8
Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with → are part of a longer accumulation, which is shown on the final day.
Values over 100 mm have been rounded to the nearest whole millimetre.
Days marked with - have a precipitation report of zero; days left blank have no precipitation report (which often indicates no precipitation fell).
Precipitations coloured
according to the amount
0 1.0 5.0 10.0 15.0 25.0 50.0 100 150 200 300 400 600 millimetres

Map of the areas covered by this summary

Notes

The Monthly climate summary lists the main features of the weather in Australia's Remote Islands and Antarctica using the most timely and accurate information available on the date of publication; it will generally not be updated. More extensive discussion of significant weather events, along with later information and data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review.

This statement has been prepared based on information available at 10 am on Monday 4 January 2021. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

In some situations, some or all of the precipitation is in the form of hail or snow. In these cases the totals given are for the water equivalent: the depth of liquid water that results from melting any frozen precipitation. There can be significant 'undercatch' of snow in strong winds, meaning the true precipitation can be higher than that reported.

Averages for individual sites are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average precipitation.

The Rank indicates how precipitation this time compares with the climate record for the site, based on the decile ranking (very low precipitation is in decile 1, low in decile 2 or 3, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much precipitation has fallen this time as a percentage of the long-term mean.

Where temperature area averages are mentioned, they are derived from the ACORN-SAT dataset.

Further information

Media
(03) 9669 4057

Climate