Perth in November 2011: Warmer than normal nights

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.
  • Rainfall: Average to above average.
  • Maximum temperature: Average for most sites but below average in the hills.
  • Minimum temperature: Above average for most sites.

Rainfall

Rainfall across the Perth metropolitan area during November 2011 was near average to above average for most of the region. Rainfall totals were generally in the 20 to 70 mm range, and Mundaring in the Perth hills received 72.6 mm, which was more than double its long-term average for November, and the highest monthly rainfall in the Perth area for the month.

Across Perth, wet conditions occurred mainly in the first half of the month, and the second half of the month saw lengthy dry spells interspersed with a couple of days of rain. A trough near the west coast combined with a middle level disturbance to produce the first widespread light to moderate rainfall across the Perth metropolitan area on the 3rd. Rain continued when a number of cold fronts followed by an unstable onshore airflow impacted the Perth region between the 4th and 8th. Daily rainfall of 34.0 mm at Mundaring on the 8th was the highest daily rainfall in the Perth area for the month.

Perth Metro recorded 29.0 mm on 8 rain days in November 2011, compared to the long-term average of 22.1 mm on 6 rain days. November rainfall totals have ranged from nil in 1891 to 73.2 mm in 1984 at Perth Metro, whilst last November (2010), Perth Metro recorded 11.6 mm on 6 rain days.

Perth Metro has recorded 785.0 mm of rainfall on 103 rain days for the year so far (January - November 2011). Though this is below the average of 837.2 mm for the January to November period, it has been the wettest such period since 796.2 mm was recorded on 110 rain days in January to November 2008.

Maximum temperature

Mean maximum temperatures were near average for most sites, though Bickley in the Perth hills was below average. Mean maximum temperatures were in the 23 to 27 °C range.

Most sites experienced three consecutive hot days (a hot day in Perth is when the daily maximum temperature is 32 °C or higher) between the 22nd and 24th, as a high pressure system moved slowly south of the state into the Bight directing dry and hot northeasterly winds over the Perth region. The 24th was the hottest day of the month with daily maxima across Perth mainland sites climbing to the mid-to-high 30s, more than 10 °C warmer than the November average.

Perth Metro's mean daily maximum temperature in November 2011 was 25.9 °C, which was close to the November average of 26.4 °C, but was the coolest November since a mean of 23.6 °C was recorded in November 2008. Daily maxima in November 2011 ranged from a mild 21.5 °C on the 8th, to a very hot 37.2 °C on the 24th. Last November (2010) was the warmest November on record at Perth Metro, since records commenced in 1897, with a mean maximum temperature of 29.6 °C.

Perth Metro's mean daily maximum temperature for the first 11 months of 2011 is 25.3 °C, the warmest January to November period since records commenced in 1897. The previous record was 24.9°C in 2010, whilst the average for the same period is 24.1 °C. This year so far, Perth Metro has also registered its greatest number of hot days on record with 67 days (32 °C or higher), exceeding the previous annual record of 66 hot days set in 1978. The annual average is 49 hot days. To reinforce the fact that Perth Metro has been experiencing unusually warm conditions over the past year or so, November 2011 was the first month to see a below average mean maximum temperature at Perth Metro since July 2010. All months since that time have been equal to or above the long-term monthly average.

Minimum temperature

Mean minimum temperatures in November 2011 were above average for most sites, and generally in the range of 13 to 16 °C .

Nights were mostly mild during November with a number of warm nights recorded (a warm night in Perth is when a daily minimum temperature is 20 °C or higher). The warmest night was the 24th for most sites with daily minima in the low-to-mid 20s. Pearce RAAF registered a minimum of 24.0 °C on the 24th, the highest overnight temperature of the month in the Perth area.

Perth Metro's mean daily minimum temperature in November 2011 was 14.9 °C, which is close to the average of 14.2 °C. Daily minima ranged from a mild 10.2 °C on the 10th to a warm 20.5 °C on the 3rd. Last November (2010) Perth Metro recorded a mean minimum temperature of 15.3 °C.

During the January to November period, Perth Metro has recorded 42 warm nights (20 °C or higher), which is the greatest number of warm nights recorded at Perth Metro for 23 years, since 52 warm nights were recorded in 1988.

Wind and Sunshine

The greatest wind gust during the month in the Perth metropolitan area was 74 km/h recorded at Rottnest Island on the 8th when a cold front passed through the Perth area.

Perth recorded an average daily sunshine of 10.2 hours per day in November 2011, the least sunshine hours for November since a daily average of 9.9 hours was recorded in 2006. The average daily sunshine hours for November is 10.7 hours.

Further information

Media
(03) 9669 4057
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Extremes in November 2011
Hottest day 38.7 °C at Medina Research Centre on the 24th
Warmest days on average 26.6 °C at Gosnells City
Coolest days on average 23.0 °C at Rottnest Island
Coldest day 16.9 °C at Bickley on the 8th
Coldest night 7.2 °C at Jandakot Aero on the 19th
Coolest nights on average 12.3 °C at Bickley
Warmest nights on average 16.7 °C at Rottnest Island
15.5 °C at Swanbourne
Warmest night 24.0 °C at Pearce RAAF on the 24th
Wettest overall 72.6 mm at Mundaring
Wettest day 34.0 mm at Mundaring on the 8th
Highest wind gust 74 km/h at Rottnest Island on the 8th


Summary statistics for November 2011
Maximum temperatures
for November
(°C)
Minimum temperatures
for November
(°C)
Rainfall
for November
(millimetres)
Mean for
November
2011
Diff
from
average
Highest for
November
2011
Mean for
November
2011
Diff
from
average
Lowest for
November
2011
Total for
November
2011
Average
for
November
Rank of
November
2011
Fraction of
November
average
Bickley 23.5 -1.4 34.0 24th 12.3 +0.6 8.5 30th 64.6 41.9 high 154%
Champion Lakes 24.9   35.1 24th 14.9   10.6 9th
Garden Island HSF 24.0 +0.2 36.9 24th 16.4 +0.8 12.9 30th 14.2 24.0 low 59%
Gosnells City 26.6 -0.8 38.2 24th 14.5 +0.2 10.3 28th 44.8 28.7 high 156%
Jandakot Aero 25.7 -0.5 37.3 24th 13.8 +1.4 7.2 19th 31.6 29.0 average 109%
Medina Research Centre 26.0 +0.1 38.7 24th 14.7 +1.4 9.1 19th 24.2 32.1 average 75%
Pearce RAAF 26.2 -0.9 37.8 24th 13.6 +1.1 8.4 10th 29.2 23.4 average 125%
Perth Airport 26.1 +0.3 37.2 24th 14.1 +1.4 9.1 10th 39.4 26.1 high 151%
Perth Metro 25.9 -0.5 37.2 24th 14.9 +0.8 10.2 10th 29.0 22.1 high 131%
Rottnest Island 23.0 0.0 32.2 23rd 16.7 +0.9 13.4 9th 19.4 17.2 average 113%
Swanbourne 25.5 +0.3 36.0 24th 15.5 +0.9 10.9 19th 35.2 23.9 high 147%

Daily maximum temperature
Central Coast (09)123456789101112131415161718192021222324252627282930
Bickley28.030.125.219.719.719.119.716.919.121.123.821.920.821.123.722.420.820.023.726.327.429.132.934.027.523.820.919.422.2
Champion Lakes30.325.921.821.520.921.420.120.722.625.423.022.022.524.723.422.721.825.727.429.731.734.935.127.724.723.521.724.2
Garden Island HSF30.531.825.423.021.922.422.620.222.022.920.822.223.923.519.422.723.520.121.224.224.531.532.636.923.720.920.521.420.3
Gosnells City34.727.923.523.022.323.020.622.824.526.224.723.824.726.125.324.223.527.026.430.833.637.438.229.526.122.825.8
Jandakot Aero31.333.525.923.522.321.422.620.921.922.824.323.423.123.724.123.224.922.325.728.029.532.036.137.327.225.023.722.224.6
Medina Research Centre31.734.227.223.222.623.223.522.323.124.423.523.324.024.023.823.725.422.324.727.629.332.936.338.727.023.823.522.023.9
Pearce RAAF32.025.722.923.522.623.421.222.523.525.724.623.724.226.524.925.623.226.529.230.332.535.637.824.223.025.1
Perth Airport31.033.926.122.922.621.922.720.821.823.325.424.322.924.125.623.924.122.926.228.929.432.435.937.228.425.724.122.625.0
Perth Metro31.233.423.823.922.622.222.621.522.023.624.723.622.824.224.523.924.022.625.528.229.533.036.337.228.024.723.522.724.3
Rottnest Island25.330.522.021.820.820.521.519.921.021.521.721.521.822.520.321.522.820.420.823.322.629.132.232.024.522.020.621.120.1
Swanbourne32.133.625.424.121.622.022.421.022.323.023.323.022.923.923.822.723.921.924.428.427.533.535.536.026.123.724.022.424.3

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
Bickley12.115.417.515.112.012.211.512.28.810.610.811.013.514.09.011.213.810.59.09.911.312.316.818.217.713.811.19.79.78.5
Champion Lakes16.620.117.415.315.013.915.910.610.813.412.116.017.812.011.616.213.411.913.514.916.521.321.719.314.314.112.312.612.7
Garden Island HSF16.920.421.017.917.517.816.016.214.216.514.716.017.918.513.313.718.415.713.013.415.016.718.919.719.816.714.516.013.812.9
Gosnells City16.520.517.515.014.512.615.510.412.411.614.814.611.411.413.512.811.514.015.416.618.221.419.714.510.312.512.8
Jandakot Aero15.920.420.516.612.913.815.116.010.29.29.012.015.817.58.59.317.010.17.212.914.616.216.717.416.713.913.511.812.012.3
Medina Research Centre15.820.121.017.415.115.316.015.710.410.611.013.017.918.411.110.717.711.59.112.813.116.518.519.518.115.114.012.512.012.2
Pearce RAAF21.217.012.713.012.414.89.58.49.111.413.316.010.08.813.312.89.813.114.715.917.624.016.212.712.612.7
Perth Airport16.018.920.816.712.513.611.415.310.59.110.112.316.718.310.09.413.611.910.813.715.216.216.218.716.714.814.913.212.712.4
Perth Metro15.919.920.517.613.913.215.815.211.210.211.213.817.118.510.511.815.312.911.213.815.016.517.720.019.115.415.213.713.412.5
Rottnest Island17.219.920.818.116.616.715.915.813.415.316.016.216.918.214.616.117.816.313.714.415.717.620.121.419.717.214.816.314.513.6
Swanbourne16.219.820.517.416.116.916.115.112.511.712.813.417.518.411.512.517.714.010.913.514.816.718.721.519.915.014.613.612.812.7

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 - - - 15.4 2.2 10.2 - 17.4 10.6 - - - - - 0.6 - - 6.6 - - - - 0.2 - - - - - 1.4 -
Champion Lakes


18.6 0.2 3.2 8.4 11.8 3.2 - - - - - - - - 3.8 - - - - - - - - - - 2.0 -
Garden Island HSF - - - 5.4 - 0.6 0.4 2.0 1.4 - - - - - 0.6 - - 1.4 - - - - - - - - - - 2.4 -
Gosnells City - »» 1.2 14.8 0.1 4.4 0.4 16.0 1.4 - - - - - - - - 3.9 - - - - - - - - - - 2.6 -
Jandakot Aero - - 2.2 11.8 - 4.4 3.0 4.2 1.2 - - - - - 0.4 - - 3.8 - - - - - - - - - - 0.6 -
Jarrahdale - - 0.4 11.0 0.4 6.8 3.2 14.0 8.4 - - - - - 0.4 - - 1.2 - - - - - - - - - - 1.8 -
Medina Research Centre - - 1.2 5.6 0.6 4.6 2.0 1.4 1.8 - - - - - - - - 1.8 - - - - - - - - - - 5.2 -
Mundaring


14.2 1.0 6.2 2.6 34.0 5.0




0.4

6.6









2.6
Pearce RAAF

- 13.6 0.2 2.4 0.8 9.0 1.0 - -
- - - - - 2.2 - - - - - - -

- - -
Perth Airport - - 1.4 14.2 0.2 3.8 1.4 14.0 1.6 - - - - - - - - 1.4 - - - - - - - - - - 1.4 -
Perth Metro - - 2.2 7.2 0.2 3.2 - 13.2 0.6 - - - - - - - - 2.2 - - - - - - - - - - 0.2 -
Roleystone
















6.2











Rottnest Island - - 0.2 8.8 0.4 2.2 - 3.0 3.0 - - - - - - - - 1.2 - 0.2 - - - - - - - - 0.4 -
Serpentine - - 1.8 11.2 0.2 5.0 2.8 10.2 4.0 - - - - - 0.2 - - 6.4 - - - - - - - - - - 2.0 -
Swanbourne - - 2.6 6.8 - 3.8 0.4 15.4 2.4 - - - - - 0.2 - - 3.0 - - - - - - - - - - 0.6 -

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 3 pm on Wednesday 30 November 2011. 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.

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 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.

Further information

Media
(03) 9669 4057
Enquiries