Adelaide Metro & Hills in April 2012: A warm and dry month

  • Below average rainfall, typically only 50% of average on the Adelaide plains, closer to average in the Adelaide hills.
  • Daytime temperatures about 2 degrees above average, and above average numbers of hot days.
  • Night time temperatures were near average.

Rainfall

The April 2012 rainfall total at Adelaide (Kent Town) was 27.0 mm received on 7 rain days. This is compared to the long-term average of 40.1 mm on 8 rain days, and the median rainfall of 33.6 mm. By comparison, during April 2011, 13.6 mm was recorded. April 2010 was the last April in Adelaide with above average rainfall with 49.6mm.

Most of the month saw only small rainfall totals from weak cold frontal systems. Much of the rainfall observed for the month came from a series of cold fronts around a strong cold air mass in the third week of the month. This event also produced significant totals in the Adelaide Hills in the persistent moist westerly airstream, resulting in totals for the month in this region being closer to average than on the plains where totals were typically only 50% of average.

Rainfall totals for April 2012 across the plains typically were ranged from 15 to 25mm with higher totals in the 25 to 50mm range in the Adelaide Hills. The wettest location for the month was Mount Barker where 49.2mm was recorded for the month, most of that occurring on the 22nd and 23rd of the month.

Note that the Adelaide official climate rainfall record is taken from the manually observed 203mm rain gauge at the Kent Town site in Adelaide. These figures may differ from totals on some Bureau of Meteorology web pages as these may be from automatic tipping bucket rain gauge readings.

Temperature

Much of the month was very much warmer than average with maximum temperatures up to 6 degrees above average in the first week. Daytime temperatures remained about 2 to 3 C above average for the month as a whole, despite a cooler burst of weather near months end associated with a strong cold air mass and sequence of cold fronts.

The mean maximum temperature recorded at the Adelaide (Kent Town) for April 2012 was 24.2C, 1.6C above the long-term mean maximum temperature of 24.6C. In comparison, April 2011 saw average maximum temperatures of 22.8C at Adelaide (Kent Town). The record highest April mean maximum in Adelaide is 26.9C set in 1923 at the West Terrace site.

During April 2012, Adelaide (Kent town) recorded 4 days where the maximum temperature exceeded 30 C against the expected long term average of 2 days above 30C. The coldest day was reported on the 23rd when the maximum reached 16.5C. The warmest day was on the 5th when 34.6C was recorded for the maximum temperature.

The hottest day across the Adelaide and Hills region was reported at Edinburgh Airport with a maximum of 35.0 C on the 5th, and the coldest day was at Mount Lofty on the 23rd with a maximum of 9.5 C.

Mean minimum temperatures were generally within 1C of the average this April. Some locations on the Adelaide Plains were slightly cooler than average, though hills locations tended to be warmer than average by about 1 C owing to above average cloud cover.

The mean minimum temperature for April 2012 at Adelaide (Kent Town) was 12.6C, just above the long term April average of 12.4 C. April 2011 saw minimum temperature for the month of 12.3 C.

The coldest minimum temperature recorded during April 2012 in the Adelaide and Hills area was 4.2C on the 11th at Mt Barker, whilst the warmest night was 21.8C at Noarlunga on the 6th.

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Extremes in April 2012
Hottest day 35.0 °C at Edinburgh RAAF on the 5th
Warmest days on average 24.9 °C at Parafield Airport
Coolest days on average 18.6 °C at Mount Lofty
Coldest day 9.5 °C at Mount Lofty on the 23rd
Coldest night 4.2 °C at Mount Barker on the 11th
Coolest nights on average 9.6 °C at Mount Barker
Warmest nights on average 13.8 °C at Noarlunga
Warmest night 21.8 °C at Noarlunga on the 6th
Warmest on average overall 18.5 °C at Noarlunga
Coolest on average overall 14.8 °C at Mount Lofty
Wettest overall 49.6 mm at Mount Barker
Driest overall 13.4 mm at Parafield Airport
Wettest day 25.8 mm at Mount Barker on the 23rd
Highest wind gust 74 km/h at Adelaide Airport on the 6th




Summary statistics for April 2012
Maximum temperatures
for April
(°C)
Minimum temperatures
for April
(°C)
Rainfall
for April
(millimetres)
Mean for
April
2012
Diff
from
average
Highest for
April
2012
Mean for
April
2012
Diff
from
average
Lowest for
April
2012
Total for
April
2012
Average
for
April
Rank of
April
2012
Fraction of
April
average
Adelaide (Kent Town) 24.2 +1.6 34.6 5th 12.6 +0.2 7.6 24th 27.0 40.1 average 67%
Adelaide Airport 23.5 +1.3 33.7 5th 12.0 +0.2 6.3 12th 26.6 35.2 average 76%
Edinburgh RAAF 24.6 +1.6 35.0 5th 11.8 +0.1 5.6 12th 16.6 30.7 average 54%
Mount Barker 21.7 +1.3 30.8 5th 9.6 +1.3 4.2 11th 49.6 58.5 average 85%
Mount Lofty 18.6   27.9 5th 11.0   4.5 11th 47.0
Noarlunga 23.3   33.9 5th 13.8   8.1 11th 28.8
Parafield Airport 24.9 +2.3 34.6 5th 11.1 -0.7 5.4 28th 13.4 39.2 low 34%

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 3 pm on Monday 30 April 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