Tuesday, 31 July 2012 - Monthly Climate Summary for Adelaide Metro & Hills - Product code IDCKGC26L0

Adelaide Metro & Hills in July 2012: Warmer and drier than normal

• Below average rainfall across the Adelaide Plains, though wettest July in 3 years, near average rainfall through the Adelaide Hills.
• After a cold start, both daytime and night-time temperatures average to above average across the Plains and Hills.

Extremes Records Summaries Important notes the top

Rainfall

Despite Adelaide (Kent Town) recording its wettest July in 3 years, rainfall through the month remained below average. 64.8 mm of rainfall was received on 19 rain days, almost half of which was recorded in the 24 hours to 9am on the 27th. This is compared to the long-term average of 75 mm on 16 rain days, with a median rainfall of 68.8 mm. By comparison, 61.4 mm was recorded through July 2011.

Rainfall totals for July 2012 typically ranged from 30 to 60mm across the Adelaide Plains while totals of 60 to 100 mm were observed in the Hills. The wettest location for the month across the Adelaide Plains was at Unley (Charles Street) which reported 71mm while Mount Barker in the Adelaide Hills was the wettest reporting 115.2 mm for the month.

Rainfall remained mostly well below average for the Adelaide metropolitan and Hills regions through the first 3 weeks of July 2012, though the wettest periods occurred between the 10th and 14th and again between 26th and 28th. In the earlier period, a trough of low pressure caused thunderstorms in central and eastern districts, with heavy rain and hail affecting parts of the Barossa Valley and Adelaide Hills. Large amounts of hail covered the hills around Rowland Flat and Lyndoch, taking on the appearance of snow. Most of the hail was small but some hailstones were up to 2 cm in diameter. The heavy rain caused localised flash flooding in Mount Barker. Rainfall totals in excess of 40 mm were recorded at several locations, most falling in less than an hour. The highest daily rainfall total for the month occurred at Birdwood (McVitties Hill) in the Mount Lofty Ranges, where 50.2 mm was recorded to 9 am on 13th. In the latter period, a trough of low pressure moved across southern and eastern parts of the State producing scattered showers resulting in falls generally between 20 to 30 mm to 9am on the 27th. Adelaide (Kent Town) recorded its wettest July day in 14 years with a total of 31.2mm to 9am on the 27th, Greenacres reported 44.4mm while Belair (State Flora Nursery) in the Mount Lofty Ranges reported 42mm.

The total winter 2012 rainfall to-date (June-July) for Adelaide is 191.2mm, resulting in the wettest start to winter in 8 years and just 30mm less than the long-term average winter (June-August) total rainfall of 221mm. Rainfall totals at Adelaide (Kent Town) for the year, up to the end of July, is now at 387.5mm making the January to July 2012 period the wettest since 2001.

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

Both maximum and minimum temperatures were generally near, though tending to above average across the Adelaide Metro and Hills regions during July 2012. With respect to both minimum (over night) and maximum (daytime) temperatures, the coldest periods occurred through the first week of July as a high pressure system dominated weather conditions and maintained mostly fine and clear skies across much of the State. Daytime temperatures were again below average from the 14th through to the 19th following the passage of a low pressure trough and cold frontal systems over southern parts of the State.

The average maximum temperature recorded at Adelaide (Kent Town) for July 2012 was 15.3°C, exactly on the lon-term July mean maximum temperature. In comparison, July 2011 saw average maximum temperatures of 15.6°C at Adelaide (Kent Town). The record warmest July mean maximum in Adelaide is 16.7°C recorded in July 1975 at the West Terrace site.

The coldest day for July 2012 was reported at Mount Lofty on the 14th when the maximum reached 6.5 °C; Adelaide (Kent Town) recorded its coldest day on July 1st with a maximum of only 12.6 °C.

The hottest day across the Adelaide and Hills region was reported at Adelaide (Kent Town) with a maximum of 19.0 °C on the 24th while the warmest days on average were at Parafield Airport with a monthly average of 15.6 °C.

Mean minimum temperatures were slightly above average across the Adelaide Plains and Hills this July. The mean minimum temperature for July 2012 at Adelaide (Kent Town) was 7.8°C, 0.3 °C above the long term July average of 7.5°C.

The coldest minimum temperature during July 2012 in the Adelaide and Hills area was -0.1 °C observed at Mount Barker on the 6th. The coolest nights on average were recorded at Mount Lofty with 5.0 °C. The warmest night was 12°C at Noarlunga on the 25th. Noarlunga also recorded the warmest nights on average with a monthly average of 8.5 °C

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top