Wednesday, 30 June 2010 - Monthly Climate Summary for Perth - Product code IDCKGC11L0
Rainfall in June 2010 was well below average across the Perth Metropolitan area. Rainfall totals ranged from about 30 mm in the north to around 70 mm in the southeast. For sites away from the coast, totals were more than 100 mm less than their normal June rainfall.
Little rainfall was recorded across the Perth region for the first 13 days of June. A cold front, followed by a second front with a slow moving middle level cloud band, brought falls mostly in the 20-30 mm range in the third week, whilst falls around 20 mm were registered from another cold front on the 23rd.
Perth Metro recorded 51.4 mm of rainfall on 7 days, which was the second driest June on record since records commenced in 1876. Perth Metro's driest June was 24.6 mm on five days in 2006. The average rainfall for June is 176.7 mm on about 16 days. Last year, Perth Metro recorded 156.2 mm on 19 days.
The 6-month (January - June) rainfall was also well below average across the Perth area. With the exception of coastal parts, 6-month rainfall totals were 100 mm below the long-term average in the Perth area. Pearce RAAF registered their driest January to June period on record with 115 mm.
January to June rainfall for Perth Metro was 205.6 mm recorded on 23 days, which was the seventh driest such period on record with the driest being 134.6 mm in 33 days in 2006. The January to June average for Perth Metro is 380.3 mm over 43 days, whilst the total for the same period last year was 222.4 mm on 35 days.
Mean maximum temperatures in June 2010 were close to average in the Perth area. The coolest place was Bickley with 16.1 °C and the warmest place was Gosnells City with 19.7 °C.
A mild to warm day was experienced on the 13th across the Perth area. Gosnells City recorded the highest daily maximum temperature of the month for the Perth area with 25.0 °C, and Bickley registered its only maximum temperature above 20 °C of the month with 21.1 °C.
Perth Metro's mean daily maximum temperature in June 2010 was 19.0 °C, which is near the average of 19.3 °C. Daily maxima ranged from a warm 24.6 °C on the 13th to a cool 15.1 °C on the 24th.
With the exception of Rottnest Island and Bickley, mean minimum temperatures in June 2010 were 1-2 °C below average for most of the Perth area.
The dry and calm weather of the last week of June contributed a few chilly mornings in the Perth area. A daily minimum temperature of -2.5 °C at Jandakot Aero on the 26th was the coldest night for the month in the Perth area, and several sites registered their lowest minimum temperature for June on record.
Perth Metro's mean minimum temperature in June 2010 was 7.1 °C, which is below the average of 8.6 °C, and was Perth Metro's coolest June since 2006. Daily minima ranged from a mild 14.0 °C on the 15th to a very cold -0.6 °C on the 26th, which is the second coldest night on record for any month for Perth Metro since records commenced at the Mount Lawley site in 1993. Perth Metro's lowest ever June temperature was -0.7 °C on the 17th June 2006. During the month, Perth Metro recorded 10 cold nights (a cold night is when the overnight minimum temperature is less than 5 °C), which was the greatest number of such nights for June since the 10 nights in 2008. The average for June is six and the most number of cold nights in June was 13 in 2006.
Gale force wind gusts were recorded at Rottnest Island on the 14th (78 km/h) and at Perth Airport on the 15th (72 km/h) as a cold front crossed the Perth area.
Perth recorded a daily average of 6.6 hours of sunshine, which is above the long term average of 5.9 hours.
|Extremes in June 2010|
|Hottest day||25.0 °C at Gosnells City on the 13th|
|Warmest days on average||19.7 °C at Gosnells City|
|Coolest days on average||16.1 °C at Bickley|
|Coldest day||11.8 °C at Bickley on the 28th|
|Coldest night||-2.5 °C at Jandakot Aero on the 26th|
|Coolest nights on average||5.5 °C at Jandakot Aero|
|Warmest nights on average||13.3 °C at Rottnest Island|
|Warmest night||16.5 °C at Rottnest Island on the 14th|
|Wettest overall||74.8 mm at Jarrahdale|
|Driest overall||28.0 mm at Pearce RAAF|
|Wettest day||26.2 mm at Gosnells City on the 23rd|
|Highest wind gust||
78 km/h at Rottnest Island on the 14th
|Record lowest June temperature|
| Lowest temperature
in June 2010 (°C)
| Previous lowest
|Bickley||2.4||on the 25th||3.0||on the 16th in 2006||17||8.0|
|Swanbourne||2.9||on the 25th||4.0||on the 11th in 1995||17||10.6|
|Summary statistics for June 2010|
|Garden Island HSF||18.5||23.0||13th||11.2||5.8||25th||54.6|
|Gosnells City||19.7||+0.2||25.0||13th||8.5||-1.3||1.5||25th||60.5||175.1||v low||35%|
|Jandakot Aero||19.2||+0.4||24.3||13th||5.5||-1.9||-2.5||26th||65.6||161.1||v low||41%|
|Medina Research Centre||19.4||+0.1||24.7||13th||7.4||-1.5||0.0||26th||60.5||147.7||v low||41%|
|Pearce RAAF||19.1||+0.3||24.4||13th||7.1||-2.3||-0.4||25th||28.0||136.5||v low||21%|
|Perth Airport||19.4||+0.5||24.7||13th||7.4||-1.6||0.2||26th||43.8||162.7||v low||27%|
|Perth Metro||19.0||-0.3||24.6||13th||7.1||-1.5||-0.6||26th||51.4||176.7||v low||29%|
|Central Coast (09)||1||2||3||4||5||6||7||8||9||10||11||12||13||14||15||16||17||18||19||20||21||22||23||24||25||26||27||28||29||30|
|Garden Island HSF||1.0||-||-||-||-||-||-||-||-||-||-||-||-||1.6||15.8||7.8||-||3.0||5.2||0.2||-||-||10.8||9.0||-||-||-||-||0.2||-|
|Medina Research Centre||-||-||-||-||-||-||-||-||-||-||-||-||-||3.2||21.6||4.8||0.1||2.2||2.0||-||-||-||19.0||7.4||0.2||-||-||-||-|
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 marked like this on the final day.
Values over 100 mm have been rounded to the nearest whole millimetre.
Days marked with - have a rainfall report of zero;
days left blank have no rainfall report (which often indicates no rain fell).
This table is very wide; you may have to scroll sideways to see all the days, and you may need to set the paper to 'landscape' to print.
A Monthly Climate Summary is prepared to list the main features of the weather in Perth 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 10 am on Wednesday 30 June 2010. 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 10 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
(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.
Records in this summary are based on sites with at least 10 years of data.
*Official Perth observations have been recorded at several different sites with varying instrumentation over the years, and these changes can affect the continuity of the climate record. For the current Mt Lawley site, the most significant changes of this kind relate to temperature and rain days.
For that reason, current mean temperature and rain-day data quoted here are based only on readings from the Mt Lawley site, which commenced observations in 1993. Sunshine recordings are from Perth Airport and for similar reasons current means use only Perth Airport data, which commenced in 1993.