Adelaide Metro & Hills in December 2011: A warm and dry end to 2011

  • Above average temperatures, despite mild conditions through much of the month.
  • Drier than average on the plains, but average rainfall in the hills.

Rainfall

Rainfall totals were typically below average on the Adelaide plains, generally about 80% of average, with totals of between 15 to 30 mm being reported. Hills locations tended closer to average, and up to 20% above average at several locations, with totals ranging from 30 to 50 mm. The highest rainfall total in the Adelaide and Hills region for December 2011 was 70.8mm at Chain of Ponds in the Adelaide Hills. Much of the month was dry, with rainfall largely occurring in two events, one a significant rain event mid-month with associated severe thunderstorm activity.

A total of 18.2 mm of rainfall was recorded on 5 rain days at Adelaide (Kent Town) during December 2011, 11.6 mm below the long term December average for this site of 29.8 mm on 7 rain days. In contrast, December 2010 saw 87.0 mm of rainfall recorded, with the driest December at the Adelaide (Kent Town) site being 5.8mm in 1991. (Note: the rainfall total for the period is from the manually observed 203mm rain gauge making up the long term rainfall record. This may differ from totals on some Bureau's webpage as these may be from the automatic tipping bucket rain gauge).

The annual rainfall total (January to December 2011) at Adelaide (Kent Town) was 537.8 mm, slightly below the long-term annual average of 550.2 mm. In 2010, 592.6 mm was recorded for the year. Well above average rainfall was reported for the first three months of the year and generally drier than normal conditions since April have kept rainfall totals near or below the long term average across the Adelaide Hills and Metropolitan area for 2011.

Temperature

Much of the month was relatively mild, with little in the way of very hot conditions occurring until about the last week of the month, when a burst of hot conditions extended into the New Year.

Average monthly maximum temperatures were generally about 1.0C above average for December 2011 across the Adelaide metropolitan and hills area. The December 2011 mean maximum temperature at Adelaide (Kent Town) was 27.9C which is 0.9C above the long-term mean maximum temperature of 27.0C. In comparison, December 2010 saw below average maximum temperatures of 26.7C at Adelaide (Kent Town). December 2003 was the warmest on record for this site, with 29.0C. Only two days with maximum temperatures exceeding 35C were recorded at Adelaide (Kent Town) in December 2011 when three or four might be expected on average, indicative of the mild conditions in place through much of the month.

The hottest day for December 2011 in the Adelaide region was on the 24th, when 39.7C was recorded at Edinburgh RAAF aerodrome. Parafield Airport recorded the warmest days on average, with maximum temperatures averaging 29.0C for the month.

The coldest December day in 2011 at Adelaide (Kent Town) was on the 18th with the maximum only reaching 20.7C, and the coldest maximum temperature recorded in the Adelaide & hills area being 14.8C at Mt Lofty on the same day. The coolest days on average were recorded at Mount Lofty, where maximum temperatures averaged 22.6 C.

Mean minimum temperatures this December were warmer than average, but by only about 0.5C. The mean minimum temperature for December 2011 at Adelaide (Kent Town) was 16.3C, which is 0.7C above the long-term mean minimum temperature. In 2010 Adelaide (Kent Town) averaged 16.0C for December minimum temperatures. The coolest December at this site was in 2001 when the average for the month was only 12.8C.

The coolest nights on average in December 2011 were recorded at Mount Barker, where minimum temperatures averaged 11.2 C. The coldest minimum temperature recorded for the month in the Adelaide and hills area was 4.7C on the 5th at Mount Lofty, whilst the warmest night was 24.7C at Adelaide (Kent Town) on the 17th.

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Extremes in December 2011
Hottest day 39.7 °C at Edinburgh RAAF on the 24th
Warmest days on average 29.0 °C at Parafield Airport
Coolest days on average 22.6 °C at Mount Lofty
Coldest day 14.8 °C at Mount Lofty on the 18th
Coldest night 4.7 °C at Mount Lofty on the 5th
Coolest nights on average 11.2 °C at Mount Barker
Warmest nights on average 16.3 °C at Adelaide (Kent Town)
Warmest night 24.7 °C at Adelaide (Kent Town) on the 17th
Warmest on average overall 22.2 °C at Parafield Airport
Coolest on average overall 17.1 °C at Mount Lofty
Wettest overall 70.8 mm at Chain of Ponds (Millbrook Resv (Saw))
Highest wind gust 76 km/h at Edinburgh RAAF on the 17th

Summary statistics for December 2011
Maximum temperatures
for December
(°C)
Minimum temperatures
for December
(°C)
Rainfall
for December
(millimetres)
Mean for
December
2011
Diff
from
average
Highest for
December
2011
Mean for
December
2011
Diff
from
average
Lowest for
December
2011
Total for
December
2011
Average
for
December
Rank of
December
2011
Fraction of
December
average
Adelaide (Kent Town) 27.9 +0.9 39.0 24th 16.3 +0.7 9.5 1st 18.2 29.8 average 61%
Adelaide Airport 26.9 +1.2 37.9 24th 15.3 +0.8 8.4 1st 24.8 24.3 average 102%
Edinburgh RAAF 28.3 +0.5 39.7 24th 15.2 +0.4 7.5 1st 25.0 25.1 average 100%
Mount Barker 25.7 +0.7 36.4 31st 11.2 +0.8 6.2 2nd 34.8 35.0 average 99%
Mount Lofty 22.6   32.3 31st 11.4   4.7 5th 49.4
Noarlunga 26.6   37.5 24th 15.7   9.0 1st 19.8
Parafield Airport 29.0 +1.4 39.5 24th 15.5 +0.7 6.7 1st 22.2 25.1 average 88%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Adelaide Metro & Hills using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 2 pm on Tuesday 3 January 2012. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages 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 20 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall 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 rain has fallen this time as a percentage of the long-term mean.

Further information

Media
(03) 9669 4057
Enquiries