Perth in November 2012: A very wet month

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.
  • Rainfall: very much above average across the Perth area, and wettest on record at some sites.
  • Maximum temperature: near average
  • Minimum temperature: near average

Rainfall

Rainfall across the Perth metropolitan area during November 2012 was very much above average, with monthly rainfall totals generally ranging from 40 mm to 80 mm, and grading to 130 mm in the Perth hills. Perth Airport and Bickley experienced their wettest November in 69 years and 42 years respectively, while a number of sites observed their wettest November for at least 10 years.

A cold front moved through the Perth region early morning on the 4th, with showers, thunderstorms and hail reported during the day. Most sites reported their heaviest rainfall for the month on the 4th with daily totals in the 20 mm to 30 mm range, whilst falls in the 10 mm to 20 mm range were recorded on the 5th. A westerly flow in the wake of the cold front produced mainly light showers on the 6th and 7th. A weak front moved across the Perth area in the evening on the 10th resulting in generally light showers across the Perth region. After a lengthy dry period from the 12th through to the 23rd, a deep surface trough and middle level disturbance moved across the Perth region on the 24th producing showers and thunderstorms across the metropolitan area. A line of thunderstorms developed over central parts of Perth at approximately 1100 WST on the 24th and moved southward through southern suburbs before thunderstorms to the north of Perth moved over the city in the late afternoon, with heavy falls in the northern and eastern suburbs and hail observed in northern suburbs. The daily total at Perth Airport of 26.0 mm in the 24 hours to 9am on the 25th was the third wettest day in November on record at the site, and 20.8 mm of this total fell in the 10 minutes from 1813 WST to 1822 WST on the 24th, which is a one in 20 to 50 year event. Daily totals at most other sites were generally less than 10 mm. A cold front moved across the Perth area early on the 28th, followed by a secondary front during the evening of the 28th, connected to a rapidly deepening low just off the the WA southwest coast. The systems brought widespread squally showers, very strong winds, and very high tides. Well exposed sites across the metropolitan area recorded maximum wind gusts in excess of 90 km/h, whilst coastal sites recorded wind gusts greater than 100 km/h, with the maximum gust reported during the event being 117 km/h at Rottnest Island. Most wind recording sites in the metropolitan area recorded their greatest November wind gusts for more than 10 years, and Perth Airport recorded its highest November wind gust since 1965. It was a rare occurrence for such a strong storm in late spring and the storm caused traffic congestion, with one lane closed on the Kwinana Freeway due to waves on the Swan River over-topping the sea wall, airport delays, and extensive power outages with reports of 50,000 houses losing power. Daily falls on the 28th and 29th were generally moderate with heavier falls in the Perth hills. Bickley recorded 40.4 mm on the 29th, the highest daily fall in the metropolitan area during November.

Perth Metro recorded 58.2 mm of rainfall on 8 rain days in November 2012, well above the long term November average, and the 7th wettest November since records commenced in 1876. The highest daily fall at Perth Metro during November 2012 was 26.0 mm on the 4th. Historically, November rainfall in Perth has ranged from 0.0 mm in 1891 to 73.2 mm in 1984, while last November (2011), Perth Metro recorded 29.0 mm on 8 rain days.

The total rainfall for the 2012 year to date (January to November) at Perth Metro is 588.0 mm on 96 rain days. This has been Perth Metro's 10th driest January to November period since records commenced in 1876. The long-term January to November average at Perth Metro is 836.7 mm.

Maximum temperature

Mean maximum temperatures in November 2012 were near average across the Perth region, with mean maxima around 23 °C on the islands, 24 °C in the hills, and 25 °C to 27 °C on the coastal plain.

November 2012 saw a cool to mild start, with below average maximum temperatures for the first week of the month and most sites reported their coolest day on the 4th when temperatures only reached the high teens in the wake of a cold front. Conditions warmed on the 9th in northeasterly winds ahead of a cold front with a number of sites recording maximum temperatures in the low thirties for the first warm day of the month. A weak front moved through on the 10th, with temperatures dropping to the low twenties on the 10th and 11th. Much of the remainder of the month saw mild to warm maxima, with hot days observed on the on the 17th and 21st as the result of a strong heat trough off the west coast. All metropolitan sites recorded their highest maxima of the month on the 17th or 21st and the daily maximum temperature of 36.9 °C at Pearce RAAF on the 17th was the highest temperature of the month in the Perth metropolitan area. Cool conditions due to strong cold fronts were experienced across Perth to end the month, with temperatures mainly in the high teens to low twenties.

Perth Metro's mean daily maximum temperature in November was 25.9 °C, below the average of 26.4 °C, and the first month to see a below average mean maximum temperature since February. Daily maxima at Perth Metro ranged from a hot 35.3°C on the 17th, to a mild 19.0°C on the 4th.

Perth Metro's mean maximum temperature for the 2012 January to November period is 25.2 °C, the 2nd highest from records commencing in 1897. The record warmest January to November period was set in last year (2011) with a mean maximum of 25.3 °C.

Minimum temperature

Mean minimum temperatures in November 2012 were also near average across the Perth area, with mean minima generally between 12 °C and 14 °C, 15 °C to 16 °C off the coast.

Perth nights were generally cool to mild for the first half of November with most sites recording their coolest morning of the month between the 9th and 13th. Jandakot Aerodrome recorded the lowest temperature in the metropolitan area in November with 7.2 °C on both the 10th and 13th. Many sites experienced warmer nights in the second half of November, particularly on the 17th, 18th, and 21st to 25th where temperatures were mostly in the mid to high teens. The 22nd was the warmest night of the month at most sites and the daily minimum temperature of 20.2 °C at Champion Lakes in the southeastern suburbs was the highest overnight temperature recorded during November.

Perth Metro's mean daily minimum temperature in November 2012 was 14.0 °C, close to the mean of 14.2 °C. Daily minima ranged from a mild 10.6 °C on the 5th to a warm 18.8 °C on the 22nd.

Sunshine

The mean daily sunshine hours for November was 10.7 hours, which is close to the average of 10.6 hours.

Further information

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Extremes in November 2012
Hottest day 36.9 °C at Pearce RAAF on the 17th
Warmest days on average 27.6 °C at Pearce RAAF
Coolest days on average 22.7 °C at Rottnest Island
Coldest day 15.0 °C at Bickley on the 29th
Coldest night 7.2 °C at Jandakot Aero on the 10th & 13th
Coolest nights on average 11.7 °C at Bickley
Warmest nights on average 15.7 °C at Rottnest Island
Warmest night 20.2 °C at Champion Lakes on the 22nd
Wettest overall 128.6 mm at Bickley
Wettest day 40.4 mm at Bickley on the 29th
Highest wind gust 117 km/h at Rottnest Island on the 28th



Record highest total November rainfall
Total rainfall
for November 2012 (mm)
Previous wettest
for November
Years of
record
Average for
November
Perth Airport 85.0 80.7 in 1946 69 26.9
Bickley 128.6 120.0 in 1984 43 44.0

Highest total November rainfall for at least 10 years
Total rainfall
for November 2012 (mm)
Most recent November
at least this wet
Years since
wetter
Average for
November
Serpentine 64.4 73.4 in 1950* 44 24.7
Jarrahdale 109.0 129.4 in 1984* 25 35.4
Pearce RAAF 59.0 61.2 in 1992 20 23.8
Gosnells City 79.8 93.4 in 1992 20 29.7

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported.




Summary statistics for November 2012
Maximum temperatures
for November
(°C)
Minimum temperatures
for November
(°C)
Rainfall
for November
(millimetres)
Mean for
November
2012
Diff
from
average
Highest for
November
2012
Mean for
November
2012
Diff
from
average
Lowest for
November
2012
Total for
November
2012
Average
for
November
Rank of
November
2012
Fraction of
November
average
Bickley 23.8 -1.0 33.4 17th 11.7 -0.1 7.8 11th 128.6 44.0 highest 295%
Champion Lakes 25.2   34.7 17th 14.3   11.0 5th 79.0
Garden Island HSF 22.9 -0.9 30.6 21st 15.3 -0.3 12.0 12th 37.8 25.1 high 151%
Gosnells City 26.6 -0.8 36.0 17th 13.7 -0.6 10.5 11th 79.8 29.7 v high 269%
Jandakot Aero 25.7 -0.4 35.7 21st 11.8 -0.7 7.2 10th 67.8 29.9 v high 227%
Medina Research Centre 26.1 +0.2 36.2 21st 12.7 -0.7 8.6 9th 45.6 32.6 average 140%
Pearce RAAF 27.6 +0.5 36.9 17th 12.0 -0.5 8.0 10th 59.0 23.8 v high 248%
Perth Airport 26.3 +0.5 36.1 17th 12.7 0.0 7.7 13th 85.0 26.9 highest 316%
Perth Metro* 25.9 -0.3 35.3 17th 14.0 -0.2 10.6 5th 58.2 22.1 high 263%
Rottnest Island 22.7 -0.3 26.7 21st 15.7 -0.1 10.0 5th 36.4 17.2 high 212%
Swanbourne 25.1 -0.2 35.8 21st 14.1 -0.5 10.3 12th 60.0 25.7 v high 233%

Daily maximum temperature
Central Coast (09)123456789101112131415161718192021222324252627282930
Bickley18.220.818.915.715.818.820.023.829.022.118.924.629.125.525.130.233.426.023.025.931.829.822.128.326.128.125.218.015.0
Champion Lakes21.021.921.918.018.520.422.225.329.822.820.725.830.426.326.331.634.726.223.926.034.330.223.629.027.229.024.520.918.2
Garden Island HSF24.723.020.218.819.220.620.424.527.122.520.222.720.520.921.724.222.821.122.324.130.629.622.825.823.225.224.221.519.3
Gosnells City21.924.524.019.020.522.224.027.231.524.527.331.827.727.432.536.027.425.535.525.530.530.826.821.919.8
Jandakot Aero22.823.721.919.019.921.522.726.231.123.621.026.029.426.725.430.034.325.924.225.035.731.023.629.527.829.725.321.819.5
Medina Research Centre23.725.821.419.719.921.522.427.731.023.423.026.027.825.524.229.034.023.425.136.231.128.029.527.628.626.122.6
Pearce RAAF22.425.523.919.021.122.724.527.833.525.222.928.132.727.929.333.736.927.426.428.035.234.125.632.329.131.330.823.720.8
Perth Airport21.723.822.318.819.821.823.126.531.623.921.826.730.927.626.731.936.126.525.326.335.132.024.930.828.230.125.922.019.2
Perth Metro22.423.322.819.019.921.823.126.531.523.821.626.931.026.626.330.435.325.425.026.135.231.824.130.028.430.225.522.019.8
Rottnest Island23.722.820.918.720.121.621.023.626.323.119.822.422.121.922.523.924.422.623.222.826.726.523.024.023.624.823.520.919.0
Swanbourne23.923.922.818.920.322.622.426.729.123.721.226.425.324.126.528.730.624.324.425.335.830.124.129.625.326.224.721.320.0

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 minimum temperature
Central Coast (09)123456789101112131415161718192021222324252627282930
Bickley10.811.411.611.18.19.410.99.011.39.87.88.710.013.011.412.613.916.512.611.012.518.313.814.113.112.915.211.79.010.0
Champion Lakes14.813.814.213.111.012.711.812.614.111.811.411.911.415.215.014.418.915.113.613.216.320.216.816.116.916.915.514.512.113.3
Garden Island HSF14.613.916.015.612.314.614.312.912.613.013.012.014.616.516.016.117.218.416.915.316.118.818.216.917.516.218.114.713.114.4
Gosnells City14.513.513.514.011.012.211.512.313.511.010.510.715.115.513.919.015.013.212.216.216.017.015.614.512.313.0
Jandakot Aero14.310.511.413.210.411.29.310.09.07.27.38.37.211.99.611.416.312.010.79.415.217.116.015.415.512.412.414.311.513.0
Medina Research Centre14.412.013.014.511.111.911.210.58.68.810.710.011.511.111.912.115.114.412.911.115.817.216.415.513.013.814.412.1
Pearce RAAF14.812.410.012.19.312.38.78.311.48.010.09.28.010.813.911.116.511.710.88.514.517.515.313.615.713.012.214.112.112.7
Perth Airport14.412.011.012.710.011.49.510.311.08.28.211.67.711.614.512.316.815.112.48.814.818.117.815.516.815.213.614.212.513.2
Perth Metro14.413.312.313.110.613.611.711.611.212.411.011.011.714.013.013.618.116.715.512.916.218.818.016.816.415.415.414.112.613.5
Rottnest Island14.415.016.214.210.013.916.214.015.515.512.813.215.416.616.616.919.018.017.417.317.019.216.917.617.817.517.014.212.313.2
Swanbourne14.113.313.013.610.914.213.811.811.512.810.910.311.014.013.213.218.917.515.013.715.819.816.816.116.115.115.913.912.613.2

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)123456789101112131415161718192021222324252627282930
Bickley 0.2 - - 37.8 20.4 3.6 0.8 - - - 3.0 - - - - - - 3.6 - - 12.0 40.4 6.8
Champion Lakes - - - 20.0 13.4 3.0 - - - - 1.0 0.2 - - - - - - - - - - - - 6.4 - - 7.6 22.8 4.6
Garden Island HSF - - 0.8 9.4 5.2 0.4 0.4 - - - 1.4 - - - - - - - - - - 0.2 - - 0.6 - - 9.2 8.6 1.6
Gosnells City - - 0.5 24.2 14.0 1.0 - - - - 0.7
- - - - - - - - - -
- 11.0 - - 6.6 15.8 6.0
Jandakot Aero - - 1.6 24.4 9.4 0.8 1.4 - - - 0.8 - - - - - - - - - - - - - 0.6 - - 7.6 16.2 5.0
Jarrahdale - - 0.2 26.2 21.8 2.8 1.6 - - 0.2 0.8 - - - - - - - - - - - - - 0.6 - - 15.6 33.6 5.6
Medina Research Centre - 0.4 - 19.2 6.3 1.9 1.6 - - - 1.0 - - - - - - - - - - - - - 0.6 - - 8.6 6.0
Pearce RAAF - - > >
31.6 0.2 0.6 - - - 0.4 - - - - - - - - - - - - - 5.8 - - 4.0 14.6 1.8
Perth Airport - - - 21.6 12.8 0.8 0.2 - - - 1.0 - - - - - - - - - - - - - 26.0 - - 4.0 17.2 1.4
Perth Metro - - - 26.0 11.2 0.4 - - - - 1.2 - - - - - - - - - - - - - 0.8 - - 8.0 9.6 1.0
Roleystone


29.0 12.4
0.2
















1.6

12.2 23.6
Rottnest Island - - 0.2 12.0 7.2 1.4 - - - - 1.2 - - - - - - - - - - - - - 0.6 - - 6.0 6.4 1.4
Serpentine - - 0.2 20.8 17.2 - 0.4 - - - 1.0 - - - - - - - - - - - - - - - - 9.0 13.4 2.4
Swanbourne - - - 21.0 16.2 - - - - - 1.6 - - - - - - - - - - - - - 1.2 - - 9.2 8.8 2.0

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 Friday 30 November 2012. 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.
The median is sometimes more representative than the mean of long-term average rain.

*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 minimum 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.

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.

Further information

Media
(03) 9669 4057
Enquiries