Friday, 30 April 2010 - Monthly Climate Summary for Perth - Product code IDCKGC21L0

Perth in April 2010

An average April for Perth

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.
  • Near avearage rainfall.
  • Near average maximum temperature.
  • Near average minimum temperature.

Details Extremes Records Summaries Important notes the top

Rainfall

Rainfall around the Perth area was generally near average, with totals generally in the 20 to 40 mm range. The only significant rainfall event was during the middle of the month when a deep low lingered off the southwest coast. The low produced almost all of Perth's April 2010 rainfall between the 12th and 16th, including the highest daily total for the month of 28.8 mm at Jandakot Aero on the 14th.

Perth Metro recorded 25.0 mm of rainfall on 6 days in April, compared with the average of 44.2 mm on about 7 days. Historically, April rainfall in Perth Metro has ranged from nil on 3 occasions, to 153.6 mm in 2008. Last April, Perth Metro registered 5.0 mm of rainfall on 2 days.

Maximum temperature

Daytime mean temperatures in the Perth area during April 2010 were near average. Daily maxima ranged from a cold 14.0 °C at Bickley on the 12th (which was also the lowest daily maximum temperature for WA in April 2010) to a hot 33.2 °C at Pearce RAAF on the 18th.

Perth Metro's mean daily maximum temperature in April 2010 was 25.0 °C, which is near the average of 25.7 °C, and was Perth Metro's coolest April since 2008. Last year, Perth Metro experienced its third warmest April on record with 27.6 °C, the warmest being 28.2 °C in 1978 and 1999. Daily maxima ranged from a hot 32.3 °C on the 18th to a cool 17.7 °C on the 12th, Perth Metro's coolest April day for four years since the 17.0 °C on 26th April 2006. Perth Metro's coldest April day on record was 13.6 °C on 16th April 1919.

Minimum temperature

Overnight mean temperatures were also near average across the Perth area in April 2010. The three lowest temperatures around Perth were observed consecutively at Jandakot Aerodrome where temperatures dropped to 6.0 °C on the 23rd; 5.8 °C on the 24th; and 4.6 °C on the 25th. Jandakot Aerodrome also recorded 6.0 °C on the 28th.

Perth Metro's mean minimum temperature in April was 13.7 °C, which is close to the average of 13.6 °C. Daily minima ranged from a mild 18.0 °C on the 3rd to a cool 7.8 °C on the 24th, which was Perth Metro's coolest night of the year so far and coolest since the 6.5 °C on 2nd October 2009. Perth Metro's coldest April night on record was 4.1 °C on 20th April 1914.

Wind & sunshine

No severe winds (winds greater than 90 km/h) were observed in the Perth area during April 2010 and wind conditions were near normal for this time of year. Rottnest Island reported the strongest gust of 81 km/h on the 13th as a low deepened off the coast.

Perth recorded sunshine of 8.2 hours, which was equal to the long-term average.

Further information

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Extremes in April 2010
Hottest day 33.2 °C at Pearce RAAF on the 18th
Warmest days on average 26.6 °C at Pearce RAAF
Coolest days on average 22.8 °C at Rottnest Island
Coldest day 14.0 °C at Bickley on the 12th
Coldest night 4.6 °C at Jandakot Aero on the 25th
Coolest nights on average 11.8 °C at Jandakot Aero
Warmest nights on average 17.0 °C at Rottnest Island
Warmest night 20.3 °C at Champion Lakes on the 19th
Wettest overall 55.6 mm at Jarrahdale
Wettest day 28.8 mm at Jandakot Aero on the 14th
Highest wind gust 81 km/h at Rottnest Island on the 13th

Details Extremes Records Summaries Important notes the top



Summary statistics for April 2010
Maximum temperatures
for April
(°C)		 Minimum temperatures
for April
(°C)		 Rainfall
for April
(millimetres)
Mean for
April
2010		 Diff
from
average		 Highest for
April
2010		 Mean for
April
2010		 Diff
from
average		 Lowest for
April
2010		 Total for
April
2010		 Average
for
April		 Rank of
April
2010		 Fraction of
April
average
Bickley 23.0 -0.5 29.6 18th 12.6 +0.2 7.3 24th 26.4 56.2 average 47%
Champion Lakes 24.7   31.5 18th 15.0   10.7 23rd 41.4
Garden Island HSF 23.2 -0.3 28.3 1st 15.7 +0.1 11.4 24th 32.4 47.2 average 69%
Gosnells City 26.2 0.0 33.1 18th 14.4 -0.2 10.0 23rd 33.0 44.3 average 74%
Jandakot Aero 25.4 -0.2 31.9 18th 11.8 -0.4 4.6 25th 49.8 43.1 average 116%
Medina Research Centre 25.3 -0.2 32.6 18th 13.2 0.0 7.0 25th 30.6 40.3 average 76%
Pearce RAAF 26.6 +0.3 33.2 18th 12.8 -0.5 7.7 26th 13.0 35.0 low 37%
Perth Airport 25.8 +0.3 32.5 18th 13.0 +0.1 7.3 28th 22.0 41.4 average 53%
Perth Metro* 25.0 -0.7 32.3 18th 13.7 +0.1 7.8 24th 25.0 44.2 average 57%
Rottnest Island 22.8 -0.8 26.8 18th 17.0 -0.1 12.9 24th 22.0 37.8 average 58%
Swanbourne 24.4 -0.7 31.8 18th 14.8 -0.2 9.9 24th 45.0 38.0 high 118%

Details Extremes Records Summaries Important notes the top

Daily rainfall
Central Coast (09)123456789101112131415161718192021222324252627282930
Bickley - - - 2.8 0.4 - - 0.6 - - - 0.6 7.2 7.2 2.6 4.8 - - - - - 0.2 - - - - - - - -
Champion Lakes - - - - - - - - - - - 0.2 2.4 14.0 23.0 1.8 - - - - - - - - - - - - - -
Garden Island HSF - - - - 0.2 0.2 0.4 - - - - 0.2 3.4 19.6 7.6 0.8 - - - - - - - - - - - - - -
Gosnells City - - - - - - - - - - - 0.8 3.6 13.8 13.4 1.4 - - - - - - - - - - - - - -
Jandakot Aero - - - 0.8 0.2 - - - - - - 0.4 4.4 28.8 10.4 4.6 0.2 - - - - - - - - - - - - -
Jarrahdale - - - 2.6 0.8 - 0.4 0.2 0.2 - - 2.6 7.0 23.6 14.6 1.4 0.4 0.2 0.2 0.2 - - - 0.4 0.2 - 0.2 0.2 0.2 -
Medina Research Centre - - - 0.2 - 0.6 - - - - - 0.8 2.4 19.4 6.2 1.0 - - - - - - - - - - - -
-
Mundaring

0.4 2.0 0.2
0.6



1.8 6.4 3.6 7.0 10.8 0.4

0.2 0.2
0.2 0.2
0.2


0.2
Pearce RAAF - - - 0.8 - - - - - - - - 0.4 6.4 3.0 2.4 - - - - - - - - - - - - - -
Perth Airport - - - 0.4 0.2 - - - - - - 0.6 3.2 11.0 0.8 5.6 0.2 - - - - - - - - - - - - -
Perth Metro - - - - - 0.2 - - - - - 0.4 2.6 11.6 3.4 6.8 - - - - - - - - - - - - - -
Rottnest Island - - - - - 1.2 - - - - - 0.2 3.4 11.4 5.6 0.2 - - - - - - - - - - - - - -
Serpentine - - - 1.2 0.6 0.2 0.2 - - - - 1.0 3.6 18.2 10.4 0.6 0.2 - - - - - - - - - - - - -
Swanbourne - - - - 0.2 - - - - - - - 7.2 25.0 8.8 3.6 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.

Details Extremes Records Summaries Important notes the top

Notes

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.

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 Friday 30 April 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 5 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.

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.

For PDF files of Perth Metro climate statistics for other months, please click here for extremes and here for averages.

Further information

Media
(03) 9669 4057
Enquiries