Perth in July 2013: near average rainfall with cold nights

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.
  • Rainfall: near average for most sites
  • Maximum temperature: near average
  • Minimum temperature: below average on the coastal plain

Rainfall

Rainfall across the Perth metropolitan area during July 2013 was near average for most sites, although Perth Airport and Rottnest Island recorded just over 70% of their normal July rainfall. Monthly rainfall totals ranged from 100 mm on offshore islands to 200 mm in the hills.

The first rainfall event in the Perth metropolitan area in July 2013 occurred on the 3rd as a weak cold front moved through the Southwest Land Division (SWLD) and rainfall totals generally less than 10 mm were reported. A strong cold front moved through the SWLD in the afternoon on the 9th, bringing significant falls across the Perth area. Jandakot Aerodrome in the southern suburbs recorded a daily total of 48.4 mm on the 10th, which was the highest daily total of the month in the Perth area. Generally light showers were recorded in the Perth area on the 12th due to the passage of a weak low pressure system. Most sites in the Perth area received moderate rainfall on the 15th and 16th as two cold fronts moved across the SWLD. After a lengthy spell of sunny weather, rainfall returned to the Perth region from the 23rd as a series of cold fronts and associated cloudbands moved through Perth bringing eight consecutive rain days. Moderate to heavy falls were reported in the 24 hours to 9am on the 24th, 26th and 27th, and 31st.

Perth Metro recorded 140.0 mm of rainfall on 15 rain days during July 2013, which is close to the long-term average of 168.7 mm. The highest daily rainfall at Perth Metro in July 2013 was 34.6 mm on the 10th. Last July (2012), Perth Metro recorded 34.6 mm on 8 rain days, which was the driest July in 136 years of record.

For winter so far (June-July 2013), Perth Metro has recorded 184.0 mm on 25 rain days, which is the fourth driest June-July period in 136 years of rainfall record. The June rainfall of 44.0 mm at Perth Metro was second driest on record.

Maximum temperature

Mean maximum temperatures in July 2013 were near average across the Perth metropolitan area. Mean maxima ranged from the mid-teens in the hills to the high teens for the coastal plain and the islands.

Relatively cool days were recorded across Perth from the 3rd to 7th, the 11th, and from the 17th to 21st, with most sites recording their coolest day of the month on the 11th or 17th. The lowest maximum temperature recorded in the Perth metropolitan area in July 2013 was 11.6 ºC at Bickley on the 17th. Relatively mild days were recorded on the 1st and 2nd, from the 13th to 15th, and on the 23rd. The warmest day across the Perth area for most sites was the 23rd, with daily maxima in the low twenties on the coastal plain and the islands, and 23.5 °C recorded at Perth Airport being the highest temperature of the month in the Perth area.

Perth Metro's mean maximum temperature in July 2013 was 18.8 °C and near the average. Daily maxima ranged from a mild 23.0 °C on the 1st to a cold 14.6 °C on the 17th.

Minimum temperature

Mean minimum temperatures in July 2013 generally ranged from below average in inland eastern coastal plain suburbs to near average for remainder of the Perth area. Mean minima were mostly in the 6 ºC to 7 °C range inland, and in the 9 ºC to 13 ºC range near the coast and on offshore islands.

Most inland sites experienced one very cold night in every three where daily minima were below 5 °C. Relatively cold nights were reported on the 1st and 2nd, from the 4th to 9th, and from the 18th to 22nd, whilst the coldest nights were the 8th, 18th and 21st when a number of sites registered sub-zero temperatures. Jandakot Aerodrome recorded a daily minimum temperature of -1.2 °C on the 8th, the lowest temperature of the month in the Perth area. Relatively cool nights were reported from the 14th to 16th, and from the 24th to the end of the month. The highest minimum temperature in the Perth metropolitan area during July was 16.3 ºC at Rottnest Island on the 15th.

Perth Metro's mean daily minimum temperature in July 2013 was near average at 6.9 °C. Daily minima ranged from a very cold 1.5 °C on the 8th to a cool 13.1 °C on the 15th.

Sunshine & Phenomena

Perth recorded an average daily sunshine of 6.6 hours in July 2013, which was slightly above the average of 6.1 hours.

A cold front moved through the SWLD on the 16th causing damaging wind gusts and heavy rainfall. Some damage to homes and fallen trees were the result in Thornlie and Wanneroo, and thousands of homes in the Perth metropolitan area were without power.

A strong cut-off low and associated cold front moved through southwest WA between the 25th and 27th with severe wind gusts reported. Department of Fire and Emergency Services received around 22 calls for help from the metropolitan area overnight on the 26th and on the morning of the 27th with damage reported in Heathridge and Beldon in the northern suburbs.

Further information

Media
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Extremes in July 2013
Hottest day 23.5 °C at Perth Airport on the 23rd
Warmest days on average 18.8 °C at Perth Metro
18.8 °C at Swanbourne
Coolest days on average 15.3 °C at Bickley
Coldest day 11.6 °C at Bickley on the 17th
Coldest night -1.2 °C at Jandakot Aero on the 8th
Coolest nights on average 5.8 °C at Jandakot Aero
5.8 °C at Pearce RAAF
Warmest nights on average 12.6 °C at Rottnest Island
8.9 °C at Swanbourne
Warmest night 16.3 °C at Rottnest Island on the 15th
14.2 °C at Swanbourne on the 15th
Wettest overall 201.6 mm at Bickley
Wettest day 48.4 mm at Jandakot Aero on the 10th
Highest wind gust 111 km/h at Rottnest Island on the 16th
98 km/h at Bickley on the 26th




Summary statistics for July 2013
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2013
Diff
from
average
Highest for
July
2013
Mean for
July
2013
Diff
from
average
Lowest for
July
2013
Total for
July
2013
Average
for
July
Rank of
July
2013
Fraction of
July
average
Bickley 15.3 +0.2 19.2 23rd 7.0 -0.1 1.7 8th 201.6 216.9 average 93%
Champion Lakes 17.8   22.0 23rd 8.3   3.7 18th 150.6
Garden Island HSF 17.9 +0.1 21.8 23rd 11.0 0.0 6.5 8th 120.0 114.3 average 105%
Jandakot Aero 18.3 +0.4 22.5 23rd 5.8 -0.9 -1.2 8th        
Pearce RAAF 18.7 +0.9 22.2 15th 5.8 -2.6 -0.9 18th 119.5 134.7 average 89%
Perth Airport 18.7 +0.8 23.5 23rd 6.6 -1.4 -0.3 18th 112.0 156.6 low 72%
Perth Metro 18.8 +0.4 23.0 1st 6.9 -0.7 1.4 18th 140.0 168.7 average 83%
Rottnest Island 18.0 +0.3 21.3 23rd 12.6 +0.3 9.2 17th 101.4 143.9 low 71%
Swanbourne 18.8 +0.5 22.4 2nd 8.9 -0.7 4.4 8th 161.0 145.7 average 111%

Daily maximum temperature
Central Coast (09)12345678910111213141516171819202122232425262728293031
Bickley18.918.614.114.715.114.013.314.916.316.013.316.617.416.818.213.911.612.713.113.212.715.619.215.317.112.715.415.415.716.4
Champion Lakes21.620.916.416.317.416.317.218.218.318.815.318.119.519.620.817.513.615.215.715.715.917.622.018.121.416.517.717.517.518.7
Garden Island HSF20.920.716.015.816.716.414.817.519.819.116.217.720.020.020.519.514.014.616.616.915.418.021.818.419.117.217.718.216.819.6
Gosnells City23.322.216.817.318.517.319.219.020.415.519.522.018.316.216.616.419.423.119.821.318.019.018.720.3
Jandakot Aero21.921.416.316.617.116.616.117.718.819.314.718.620.520.621.219.514.315.516.516.416.218.322.518.920.117.518.718.717.619.9
Medina Research Centre22.422.116.616.818.517.017.219.019.521.016.020.021.021.520.619.114.417.217.015.619.022.719.520.7
Pearce RAAF22.122.017.017.417.217.316.518.519.120.615.618.921.021.322.220.115.015.917.016.315.818.719.920.917.618.619.019.920.5
Perth Airport22.521.617.417.317.617.016.718.519.619.515.019.420.920.422.218.015.016.116.616.416.018.723.519.221.217.118.819.318.220.2
Perth Metro23.022.117.216.817.417.316.818.519.420.415.018.720.621.021.419.414.616.217.116.516.319.122.719.820.417.618.819.418.820.3
Rottnest Island21.220.915.715.817.115.614.618.119.819.416.217.319.720.721.319.414.614.516.215.616.418.421.318.519.517.418.518.517.619.5
Swanbourne22.122.416.917.618.417.517.118.718.819.915.018.020.321.320.719.415.516.917.316.717.219.222.320.120.417.518.319.819.320.1

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.
The temperatures in this table are coloured by
their difference from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C difference from average


Daily minimum temperature
Central Coast (09)12345678910111213141516171819202122232425262728293031
Bickley7.67.210.96.23.33.23.31.76.18.47.28.78.410.212.211.25.73.35.64.83.72.06.310.07.89.37.58.48.58.710.7
Champion Lakes6.76.110.26.06.16.86.34.86.18.48.19.95.99.914.911.18.93.76.15.83.95.511.411.211.012.09.68.210.09.812.6
Garden Island HSF9.311.413.99.78.58.27.76.59.210.611.813.111.412.616.013.710.38.29.78.38.18.711.213.712.712.912.111.712.612.914.8
Gosnells City3.69.45.84.56.36.45.97.25.89.65.08.511.28.54.84.29.011.113.27.66.8
Jandakot Aero0.70.89.94.72.33.81.5-1.23.86.43.59.73.310.512.69.87.9-0.82.50.8-0.61.16.513.28.911.810.66.98.67.711.1
Medina Research Centre3.12.910.26.12.34.54.51.04.68.06.29.55.011.58.30.82.71.34.210.013.310.612.4
Pearce RAAF2.51.06.32.61.84.83.70.53.57.38.210.43.510.510.510.18.3-0.91.30.8-0.95.08.611.66.912.19.68.16.56.99.0
Perth Airport4.62.29.43.93.84.83.72.53.48.57.09.95.69.611.211.98.7-0.33.51.60.95.57.511.79.812.67.98.16.58.211.5
Perth Metro4.03.28.95.72.24.02.41.54.79.36.39.66.69.413.111.59.11.43.72.03.13.36.012.210.112.79.19.48.19.612.0
Rottnest Island13.913.713.311.311.110.89.510.312.713.514.413.813.816.116.314.89.210.311.010.210.210.812.913.713.311.710.613.614.113.715.0
Swanbourne8.37.211.97.75.45.84.74.48.39.98.610.27.910.114.213.18.54.86.65.65.05.710.213.710.412.39.411.89.410.813.0

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.
The temperatures in this table are coloured by
their difference from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C difference from average


Daily rainfall
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 31
Bickley - - 1.8 0.2 - - - 0.2 - 29.2 - 8.6 - 1.0 - 18.8 23.2 - 0.2 - - 0.2 - 25.8 4.6 31.4 36.4 4.8 1.0 1.6 12.6
Champion Lakes - - 2.8 0.2 - - - - - 48.2 - 3.0 0.2 - - 8.6 17.4 - - - - - - 29.8 1.0 10.0 13.4 3.8 1.4 0.4 10.4
Garden Island HSF - - 1.6 6.6 - - - - - 30.2 - 0.2 - 0.4 0.8 6.2 9.2 - - - - - - 17.6 0.4 14.2 9.4 4.0 7.6 4.6 7.0
Jandakot Aero - - 4.0 1.4 - - - - - 48.4 -
- 0.2 - 10.6 18.0 - - - - - - 36.6 6.0 18.0 9.4 3.0 1.2 - 8.4
Jarrahdale 0.2 0.2 2.8 1.0 0.2 - 0.2 0.4 - 20.4 0.2 6.4 0.4 - - 17.8 16.0 - 0.2 - 0.2 - - 47.8 2.4 21.8 30.8 5.6 0.8 1.4 14.6
Medina Research Centre - - 2.0 1.2 - - - - - 26.6 0.4 »» »» »» 0.6 7.8 12.2 0.2 - - - - - 20.4 5.2 12.6




Pearce RAAF - - 2.4 0.6 - - - - - 11.6 - 8.6 - 0.2 - 11.4 15.6 - - - - - - 10.9 1.8 11.6 32.6 3.6 0.2 - 8.4
Perth Airport - - 3.0 0.8 - - - - - 22.4 - 1.8 - 0.4 - 9.6 12.6 - - - - - - 15.0 2.2 15.6 19.6 2.4 - 0.8 5.8
Perth Metro - - 3.2 2.0 - - - - - 34.6 - 2.2 - 1.2 - 15.0 12.6 - - - - - - 19.2 3.8 10.4 17.6 5.4 1.0 0.4 11.4
Roleystone - - 2.6 0.2 - - - - - 34.6 0.2 7.0 - - 0.2 17.8 19.0 - - - - - - 29.0 1.6 13.6 30.0 4.6 1.2 2.6 12.6
Rottnest Island - - 6.0 4.8 0.2 - - - - 17.0 - - - - 0.8 6.2 10.2 - - - - - - 16.6 0.8 6.8 9.8 8.6 0.2 4.4 9.0
Serpentine - - 2.2 0.2 - - - - - 11.0 - 2.2 0.2 - - 8.8 11.6 - - - - - - 25.4 1.4 12.4 20.6 3.4 0.4 1.8 12.4
Swanbourne - - 11.4 4.8 - - - - - 16.6 - 4.0 0.2 2.0 0.2 18.2 15.4 - - - - - - 24.8 2.2 12.6 22.0 12.4 0.2 1.0 13.0

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.


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 Wednesday 31 July 2013. 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 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.

The ACORN-SAT dataset is being used for temperature area averages from December 2012 onwards. The major change from earlier datasets is that the ACORN-SAT dataset commences in 1910, rather than 1950, and hence rankings are calculated using a larger set of years.

Further information

Media
(03) 9669 4057
Enquiries