Remote Islands and Antarctica in September 2017

Australia's Indian Ocean islands

  • Temperatures were a little above average for the Cocos (Keeling) Islands and Christmas Island by both day and night
  • Cocos Islands Airport recorded 23.4 mm of rain, about one quarter the long-term average
  • Total rainfall of 18.4 mm at Christmas Island Aero was below the long-term mean, and just a fraction of the 702 mm recorded during the exceptionally wet September last year

Australia's Pacific Ocean islands

  • Daytime temperatures on Lord Howe Island were a little above average overall, with cool weather around the 9th and 17th offset by warmer days around the 5th, 24th and 29th
  • Lord Howe Island's overnight temperatures were a little above average overall, but ranged from a chilly 8.4 °C on the morning of the 12th to a mild 19.7 °C on the morning of the 25th
  • It was the driest September on record on Lord Howe Island, with the 40.2 mm recorded at the airport about one-third of the long-term average
  • Temperatures on Norfolk Island were a above average overall: most days and nights were above average, but there were some cool mornings around the middle of the month
  • Rainfall on Norfolk Island was less than two-thirds of the September average

Australia's Antarctic and sub-Antarctic territories

  • It was another month of below-average temperatures at Australia's Antarctic sites, particularly at Casey and Davis where temperatures were more than two degrees below the long-term average for September
  • Casey reported its lowest September temperature on record with an overnight minimum of -33.8 °C on the 28th (although the old site reported a lower temperature in 1982)
  • Overnight temperatures were a degree above the long-term average on Macquarie Island, with daytime temperatures about half a degree above average
  • Macquarie Island had its wettest September day on record on the 19th: the automatic gauge reported 31.0 mm and the manual gauge 27.2 mm, both ahead of the previous record of 25.4 mm from the 1st in 2005. As a result, the island had its wettest September on record, with 139.6 mm almost double the long-term average

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Record highest September daily precipitation
New record
(mm)
Old
record
Years of
record
Macquarie Island 31.0 on the 19th 25.4 on the 1st in 2005 70



Record highest September total precipitation
New record
(mm)
Old
record
Years of
record
Average for
September
Macquarie Island 139.6 134.2 in 2002 69 75.3



Record lowest September total precipitation
New record
(mm)
Old
record
Years of
record
Average for
September
Lord Howe Island Aero 40.2 45.4 in 2003 29 114.8



Record lowest September temperature
New record
(°C)
Old
record
Years of
record
Average for
September
Casey -33.8 on the 28th -32.9 on the 19th in 2015 29 -17.1



Summary statistics for September 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Precipitation
(millimetres)
Mean for
September
2017
Diff
from
average
Highest for
September
2017
Mean for
September
2017
Diff
from
average
Lowest for
September
2017
Total for
September
2017
Average
for
September
Rank of
September
2017
Fraction of
September
average
Offshore Islands (district 200)
Christmas Island Aero 26.3 0.0 27.7 22nd 22.7 +0.4 21.6 27th 18.4 56.5 average 33%
Cocos Island Airport 28.4 +0.2 30.0 10th 24.2 +0.3 22.3 27th 23.4 94.1 low 25%
Lord Howe Island Aero 20.2 +0.2 22.7 29th 15.2 +0.6 8.4 12th 40.2 114.8 lowest 35%
Norfolk Island Aero 19.6 +0.5 22.0 30th 14.2 +0.4 11.5 14th 55.2 93.3 low 59%
Antarctica and Macquarie Island (district 300)
Casey -12.3 -2.6 -4.7 9th -19.8 -2.7 -33.8 28th 11.8 17.0 average 69%
Davis -14.7 -1.9 -7.2 23rd -22.7 -2.9 -31.5 3rd 9.4 5.5 high 171%
Macquarie Island 5.9 +0.5 7.2 5th 2.5 +0.9 0.1 8th 139.6 75.3 highest 185%
Mawson -15.1 -0.9 -9.8 24th -22.1 -1.6 -27.6 4th
Note: Precipitation values from Casey and Davis should be used with caution.

Daily maximum temperatures for September 2017
Offshore Islands (200)123456789101112131415161718192021222324252627282930
Christmas Island Aero26.225.825.825.725.726.126.226.527.226.526.726.527.226.427.227.026.027.327.426.826.927.727.126.926.224.524.424.325.024.5
Cocos Island Airport27.527.928.227.827.427.527.228.328.930.029.428.928.828.328.629.529.229.429.229.229.228.829.027.827.528.426.026.927.828.2
Lord Howe Island Aero18.218.120.121.721.919.719.419.417.718.219.220.921.720.419.720.518.319.120.819.119.620.921.722.021.821.120.121.922.720.9
Norfolk Island Aero18.518.518.119.120.421.520.520.118.718.418.218.418.820.021.220.220.118.418.019.219.519.519.119.520.821.519.319.920.322.0
Antarctica and Macquarie Island (300)123456789101112131415161718192021222324252627282930
Casey-7.4-7.0-6.8-5.7-6.1-6.1-9.6-5.4-4.7-4.8-12.3-12.0-12.5-12.6-11.5-13.4-14.3-16.1-16.4-17.1-8.0-7.3-14.4-10.8-18.0-17.9-24.1-25.4-22.3-18.7
Davis-21.6-18.0-7.6-14.1-14.4-20.7-16.7-13.1-9.5-7.7-10.5-13.5-15.9-14.9-15.4-18.5-13.8-11.3-16.9-14.2-14.4-19.3-7.2-9.7-13.4-19.2-16.2-19.9-14.9-17.7
Macquarie Island6.46.56.97.07.26.45.23.53.15.86.46.34.44.15.64.85.26.76.05.46.47.06.66.64.45.86.57.16.75.6
Mawson-17.8-17.2-16.9-20.2-18.8-14.9-16.0-13.2-10.0-11.7-9.8-12.0-16.7-20.2-19.9-15.5-13.1-12.7-14.5-17.5-14.9-16.5-11.7-9.8-13.3-15.6-15.7-16.2-15.3-14.1
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 September 2017
Offshore Islands (200)123456789101112131415161718192021222324252627282930
Christmas Island Aero22.622.922.522.822.722.223.023.223.123.322.922.622.522.423.322.923.623.122.822.822.422.723.122.822.022.821.621.922.122.1
Cocos Island Airport23.523.823.924.323.322.423.724.025.325.425.525.224.724.624.624.325.325.725.325.024.824.824.124.323.823.222.322.523.123.2
Lord Howe Island Aero13.413.211.214.419.417.116.215.113.213.013.18.418.318.513.215.416.113.712.516.615.010.117.218.719.719.516.114.317.714.4
Norfolk Island Aero12.513.911.914.513.016.816.714.615.013.513.611.611.811.516.815.413.313.614.014.615.814.614.312.314.616.716.914.113.615.5
Antarctica and Macquarie Island (300)123456789101112131415161718192021222324252627282930
Casey-23.2-21.5-11.0-12.7-9.7-10.4-14.1-14.4-11.3-8.9-16.3-15.5-15.8-20.0-18.0-21.3-21.6-23.1-24.5-21.4-22.1-21.8-18.3-24.7-22.7-23.7-29.8-33.8-32.2-30.8
Davis-29.0-31.3-31.5-19.2-17.7-29.2-26.4-25.1-19.4-15.7-11.7-19.2-20.9-20.7-20.8-21.5-25.3-21.2-22.3-20.8-21.3-21.7-24.6-20.6-14.7-26.8-26.2-25.6-25.0-25.2
Macquarie Island3.75.24.02.95.44.12.30.10.51.41.25.13.53.40.92.01.01.45.02.12.55.23.42.11.10.30.42.81.81.5
Mawson-25.6-27.0-22.7-27.6-27.6-26.0-23.4-26.9-26.1-14.0-14.6-14.3-20.3-22.8-23.9-23.3-20.1-15.9-17.7-21.3-21.1-26.4-24.4-18.0-19.6-22.5-21.7-22.7-21.7-24.4
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 September 2017
Offshore Islands (200)123456789101112131415161718192021222324252627282930
Christmas Island Aero - - 0.4 - - 0.6 0.2 0.2 - - - - - - - - - - - - - - - 0.2 0.2 - 10.0 2.8 1.6 2.2
Cocos Island Airport 3.8 0.4 0.4 1.0 2.6 - 0.8 0.2 - - - - - - - 0.6 - - - - - - - - - 0.6 4.4 3.0 0.8 4.8
Lord Howe Island (Milky Way) 6.8 6.6 0.2 - 0.4 - - 2.4 2.0 8.2 1.6 0.2 - - 21.0 0.2 0.8 - - 0.6 0.2 - - - - 0.8 - - - 0.2
Lord Howe Island Aero 5.2 3.8 0.6 - 0.2 - - 2.2 2.6 1.2 1.6 0.2 - - 17.4 0.4 2.6 - 0.2 0.8 0.2 - - - - 0.6 0.2 - - 0.2
Norfolk Island Aero 14.4 2.2 5.8 - - - - 0.2 1.8 3.4 0.6 0.2 2.6 - 0.2 1.2 0.2 - - - 5.8 0.2 - - - - 16.2 - - 0.2
Antarctica and Macquarie Island (300)123456789101112131415161718192021222324252627282930
Casey - 2.0 0.6 - - 0.2 - - - - 0.2 1.0 2.0 - -
- - - - - 1.2 1.0 - 3.2 - 0.4 - - -
Davis 0.2 - 0.4 0.2 1.2 - - - - - 0.2 0.1 0.1 0.2 - - - - - - - - - 3.6 3.2 - - - - -
Macquarie Island 0.2 0.8 4.0 5.8 6.8 0.4 1.4 0.2 4.0 3.2 1.0 3.6 2.0 1.6 1.2 1.2 4.0 - 31.0 - 0.2 6.8 1.6 12.2 21.8 3.2 2.0 2.0 5.8 11.6
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, generally published on the first working day of each month, lists the main features of the weather in 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 2 October 2017. 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
Enquiries

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