Perth in June 2015: Dry with record warm days

It was the warmest June on record across the Perth metropolitan area in terms of day-time temperatures, whilst overnight temperatures were also above average. Rainfall was well below average.

  • Warmest June day-time temperatures on record
  • Above average overnight temperatures
  • Below average rainfall
  • Record equalling number of mild days at Perth Metro

Rainfall was well below average across the metropolitan area in June with most sites recording close to 50% of their normal June rainfall. Rainfall events were observed on the 1st and 2nd, with most sites reporting light falls continuing through to the 7th, whilst heavy falls were reported from the 17th to 22nd, with most sites recording the majority of their June 2015 rainfall during this period. Perth Metro at Mount Lawley recorded a total of 100.4 mm on 11 rain days, which is well below the long-term average of 173.9 mm for the Perth official site (records commenced in 1876).

All Perth metropolitan recording sites experienced their warmest June on record in terms of mean maximum temperatures. Most days were mild to warm with daily maximum temperatures in the low to mid-twenties, and the warmest day for most sites was the 11th (Medina recorded its warmest June day on record), as a strong high pressure directed warm northerly winds over Perth. Only a few cool to cold days with daily maxima in the mid-to-high teens were reported, most notably on the 22nd and 23rd. All sites recorded their coolest day for June 2015 on the 22nd.

Perth Metro recorded a total of 21 days with daily maximum temperatures at or above 20 °C, which is the the equal highest number of such days on record for the Perth official site, equal with June 1983.

Mean minimum temperatures were also above average across Perth. For the first three weeks of the month, nights were mostly cool to mild with daily minimum temperatures in the low to mid-teens, interspersed with a few cold nights. The mildest night was either the 3rd or 20th, and Jandakot Aerodrome registered its warmest June night on record on the 3rd in a westerly air-stream, whilst Bickley and Swanbourne registered their warmest June night on record on the 20th in northwesterly winds as a cut-off low moved past the southwest corner of the State. In the last week of the month, nights were generally cold to very cold across the coastal plain and in the hills, with the coldest night of the month being the 23rd for all sites.

Many sites also broke their highest June mean temperature on record, whilst Perth Airport had its highest June mean temperature since 1983.

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Extremes in June 2015
Hottest day 26.5 °C at Medina Research Centre on the 11th
Warmest days on average 21.2 °C at Pearce RAAF
21.2 °C at Swanbourne
Coolest days on average 17.4 °C at Bickley
Coldest day 12.6 °C at Bickley on the 22nd
Coldest night 0.4 °C at Jandakot Aero on the 23rd
Coolest nights on average 8.2 °C at Jandakot Aero
Warmest nights on average 14.2 °C at Rottnest Island
11.4 °C at Swanbourne
Warmest night 17.7 °C at Garden Island HSF on the 20th
16.2 °C at Medina Research Centre on the 20th
Warmest on average overall 16.9 °C at Rottnest Island
16.3 °C at Swanbourne
Coolest on average overall 13.2 °C at Bickley
Wettest overall 132.6 mm at Bickley
Driest overall 53.8 mm at Medina Research Centre
Wettest day 57.2 mm at Roleystone on the 21st
Strongest wind gust 96 km/h at Rottnest Island on the 21st

Record highest June temperature
New record
(°C)
Old
record
Years of
record
Average for
June
Medina Research Centre 26.5 on the 11th 26.2 on the 3rd in 1984 30 19.4



Record highest June mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
June
Perth Metro* 21.0 20.6 in 1983 117 19.3
Perth Airport 21.0 20.7 in 1983 71 18.9
Pearce RAAF 21.2 20.6 in 1983 54 18.8
Medina Research Centre 20.9 20.8 in 2000 29 19.4
Rottnest Island 19.7 = 19.7 in 1997 25 18.7
Jandakot Aero 20.7 19.8 in 2006 24 19.0
Gosnells City 21.1 20.7 in 2006 23 19.6
Bickley 17.4 17.2 in 2001 21 16.1
Swanbourne 21.2 20.2 in 2006 21 19.4



Record highest June daily minimum temperature
New record
(°C)
Old
record
Years of
record
Average for
June
Jandakot Aero 16.3 on the 3rd 16.2 on the 22nd in 2004 25 7.4
Bickley 15.0 on the 20th 14.0 on the 22nd in 2004 22 8.1
Swanbourne 17.1 on the 20th 17.0 on the 2nd in 1998 22 10.6



Record highest June mean temperature
New record
(°C)
Old
record
Years of
record
Average for
June
Rottnest Island 16.9 = 16.9 in 2004 25 16.0
Bickley 13.2 13.0 in 2004 21 12.1
Swanbourne 16.3 16.2 in 2004 21 15.0

Highest June mean temperature for at least 20 years
Observed
(°C)
Most recent
higher
Years since
higher
Average for
June
Perth Airport 15.5 16.1 in 1983 32 13.9
Perth Metro* 15.3 15.7 in 1992 23 13.9

Summary statistics for June 2015
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
June
2015
Diff
from
average
Highest for
June
2015
Mean for
June
2015
Diff
from
average
Lowest for
June
2015
Total for
June
2015
Average
for
June
Rank of
June
2015
Fraction of
June
average
Bickley 17.4 +1.3 21.9 11th 9.0 +0.9 3.8 23rd 132.6 199.3 low 67%
Garden Island HSF 20.0 +1.0 23.3 11th 12.9 +0.8 6.7 23rd 54.2 109.1 low 50%
Gosnells City 21.1 +1.5 25.6 11th 10.2 +0.5 4.0 23rd 88.6 169.0 low 52%
Jandakot Aero 20.7 +1.7 25.0 11th 8.2 +0.8 0.4 23rd 82.4 156.6 low 53%
Medina Research Centre 20.9 +1.5 26.5 11th 10.1 +1.2 1.0 23rd 53.8 140.8 v low 38%
Pearce RAAF 21.2 +2.4 25.4 11th 9.6 +0.2 2.8 23rd 64.6 132.3 low 49%
Perth Airport 21.0 +2.1 24.9 11th 10.0 +1.0 1.8 23rd 92.4 158.2 low 58%
Perth Metro* 21.0 +1.7 25.1 11th 9.6 +1.1 2.3 23rd 100.4 173.9 low 58%
Rottnest Island 19.7 +1.0 22.2 3rd 14.2 +0.9 9.2 23rd 58.4 98.1 low 60%
Swanbourne 21.2 +1.8 24.6 11th 11.4 +0.8 4.3 23rd 109.6 124.2 average 88%

*note:Observations for Perth Metro are taken from the current Mount Lawley site, which opened in February 1993. Comparisons are made combined data from current site and the Perth Regional Office site, which ran from 1876 to early 1992.


Daily maximum temperatures for June 2015
123456789101112131415161718192021222324252627282930
Bickley18.016.318.320.120.117.818.118.118.719.821.917.815.915.416.417.615.017.019.218.314.912.613.716.716.816.315.116.820.719.7
Garden Island HSF21.020.421.321.721.520.820.319.422.223.223.318.716.918.519.720.418.821.022.321.018.914.815.217.818.818.718.720.221.621.4
Gosnells City21.721.423.221.021.121.123.525.620.918.318.720.023.521.819.115.618.620.021.021.919.420.824.023.5
Jandakot Aero21.421.022.622.423.120.920.920.222.523.525.020.717.818.519.321.018.920.923.121.719.215.716.819.719.720.418.720.123.322.0
Medina Research Centre21.422.222.923.023.321.020.819.722.024.226.520.421.221.020.020.718.021.223.522.118.915.416.919.620.620.519.020.3
Pearce RAAF21.521.823.123.623.720.221.021.023.224.825.421.318.518.719.221.820.522.824.122.319.515.616.419.920.320.718.820.123.423.2
Perth Airport21.421.022.522.823.221.521.521.022.924.324.921.318.318.819.421.619.220.723.321.819.215.616.919.520.420.718.820.223.523.5
Perth Metro20.920.922.722.923.420.821.720.822.923.825.120.817.818.819.421.819.421.323.322.419.415.816.819.720.720.719.120.324.423.2
Rottnest Island20.620.922.222.121.320.721.019.521.522.122.119.116.317.717.620.218.820.621.221.818.615.115.417.718.718.317.819.421.720.3
Swanbourne21.921.122.222.923.321.122.121.722.824.224.620.518.719.520.121.519.722.322.722.719.015.416.919.320.421.919.421.023.722.8
Values are the maximum temperature, usually in the 24 hours from 9 am on the day indicated,
and typically occurred in the afternoon of that day.
Temperatures coloured according to 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 Grey outline marks highest
and lowest for the period

Daily minimum temperatures for June 2015
123456789101112131415161718192021222324252627282930
Bickley8.110.412.112.510.712.710.59.57.68.810.213.47.65.76.18.110.510.211.015.012.16.13.84.86.17.48.56.86.18.9
Garden Island HSF11.614.916.816.513.816.614.411.512.714.414.515.912.39.79.811.815.413.315.217.715.011.46.78.310.010.911.112.010.812.0
Gosnells City6.812.714.111.68.27.912.814.414.410.49.99.511.615.814.57.84.05.85.66.011.110.110.78.2
Jandakot Aero3.410.716.312.46.911.26.96.88.611.111.813.16.02.02.97.014.313.414.815.114.28.10.41.01.35.15.97.74.24.0
Medina Research Centre6.112.817.013.08.912.18.09.49.812.414.413.76.89.08.510.113.813.115.016.214.28.61.02.63.56.99.09.18.2
Pearce RAAF7.511.913.29.67.49.64.84.812.912.714.711.86.88.48.38.914.713.115.015.513.88.42.84.44.96.39.410.011.26.3
Perth Airport7.212.012.711.69.411.78.06.211.412.414.412.48.66.37.39.913.713.115.116.014.38.01.84.17.67.39.47.49.910.1
Perth Metro6.412.115.812.69.212.29.07.09.712.911.013.38.35.35.19.514.513.214.915.814.210.02.34.24.56.87.68.56.86.4
Rottnest Island14.914.916.217.116.217.216.015.113.515.316.417.413.310.811.512.915.413.615.517.614.79.99.210.313.414.212.312.313.814.3
Swanbourne10.113.816.314.512.213.710.710.211.412.913.614.410.17.77.511.714.513.614.917.114.89.94.36.96.99.79.510.09.69.8
Values are the minimum temperature, usually in the 24 hours to 9 am on the day indicated,
and typically occurred that morning.
Temperatures coloured according to 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 Grey outline marks highest
and lowest for the period

Daily rainfall for June 2015
123456789101112131415161718192021222324252627282930
Bickley - 13.4 6.6 5.6 0.2 0.8 0.6 0.2 - - 0.2 - 0.2 - - 0.2 - 1.8 17.4 9.2 54.6 20.6 - 0.4 0.2 - 0.2 0.2 -
Garden Island HSF - 10.6 1.6 - 0.2 0.2 - - - - - 1.2 - - - - - 4.8 6.2 6.0 14.6 8.2 - - - 0.6 - - - -
Gosnells City 6.8 3.6 5.2 28.0 43.6 - - - - - - - - -
Jandakot Aero - 9.8 3.0 2.6 - 1.4 0.6 - - - - - - - - - - 1.6 7.0 6.6 30.2 19.4 0.2 - - - - - - -
Jarrahdale 0.2 14.0 8.2 1.4 0.2 1.2 0.2 0.2 0.4 - - 0.6 - 0.2 0.2 - - 1.4 5.8 9.8 31.8 24.8 0.2 0.2 0.2 - 0.2 0.2 0.2 -
Medina Research Centre - 9.6 0.8 0.6 0.1 1.4 0.3 0.4 - - - 0.6 - - - - - 2.8 4.6 5.7 16.3 10.4 0.1 - - - 0.1 - -
Mundaring - 8.6 3.4 2.6 0.4 1.2 0.2 0.2 - - - - 0.2 - - - - 1.8 8.2 14.4 29.2 18.0 0.2 0.2 0.2




Pearce RAAF - 4.0 0.8 - - - 1.2 - - - - - - 0.2 - - - 2.8 6.6 14.4 15.2 19.4 - - - - - - - -
Perth Airport - 4.6 2.8 2.0 - -
- - - - - - - - - 0.2 1.6 25.8 6.0 33.2 16.2 - - - - - - - -
Perth Metro - 5.2 2.0 3.2 - 0.2 0.6 - - - - 0.4 - - - - - 3.2 23.4 15.8 33.0 13.4 - - - - - - - -
Roleystone - 7.4 0.8 4.2 - - 1.6 - - - - 0.4 - - - - - 2.0 10.4 23.0 57.2 21.6







Rottnest Island - 15.4 - 0.8 0.4 0.4 - - - - - - 0.4 - - - - 4.2 5.4 7.8 17.0 5.8 0.2 - - 0.6 - - - -
Serpentine - 6.4 2.8 0.2 - 0.8 - - - - - 0.4 0.2 - - - - 0.8 3.2 15.0 25.6 17.2 - - - - - - - -
Swanbourne - 9.2 1.2 2.4 0.4 1.0 0.2 - - - - - - - - - - 1.2 18.8 13.6 37.0 24.2 - 0.2 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 shown 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).
Rainfalls coloured
according to the amount
0 1.0 5.0 10.0 15.0 25.0 50.0 100 150 200 300 400 600 millimetres

Notes

The Monthly climate summary lists 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.

A climate summary is generally published on the first working day of each month.

This statement has been prepared based on information available at 10 am on Wednesday 1 July 2015. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Observations for Perth Metro are taken from the current Mount Lawley site, which opened in February 1993. Comparisons are made combined data from current site and the Perth Regional Office site, which ran from 1876 to early 1992.

Averages for individual sites 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 used for temperature area averages.

Further information

Media
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