Perth in spring 2012: A warm spring

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 to above average
  • Minimum temperature: near average

Rainfall

Near average rainfall in September, a dry October, and a wet November culminated in near average to above average rainfall totals across the Perth metropolitan area during spring 2012. Rainfall totals were in the 120 mm to 200 mm range, grading to 300mm to 400 mm in the Perth hills. Bickley observed its wettest spring in 43 years of record, with a very wet September and record wet November, while Jarrahdale in the southeastern recorded its wettest spring since 1991. Please refer to the individual Perth monthly climate summaries for further details.

Perth Metro recorded 164.6 mm of rainfall on 29 rain days during spring 2012, which was near the average of 155.2 mm on 30.4 rain days. Rainfall totals at Perth Metro for the individual months in spring 2012 were: September: 90.8 mm (average 80.8 mm), October: 15.6 mm (average 52.3 mm), and November 58.2 mm (average 22.1 mm).

Maximum temperature

Day-time temperatures for spring 2012 were generally above average, with mean daily maxima in the low to mid twenties.

The Perth area experienced a few hot days during spring 2012. Daily maxima were in low to mid thirties for most sites on the 1, 27 and 28 October, and 17 and 21 November as the result of troughs off the west coast directing northeasterly winds over the city. The highest temperature recorded in the metropolitan area during spring 2012 was 36.9 °C at Pearce RAAF on 17 November. The coolest spring days were confined to 4 and 27 September, with maxima mostly in the mid-teens, whilst Bickley recorded the lowest maximum in the metropolitan are on 27 September with 10.9 °C.

Perth Metro's mean daily maximum temperature for spring 2012 was 24.1 °C, which was the second warmest spring on record, behind 25.3 °C observed in spring 2010. Daily maxima during spring ranged from a cold 14.9 °C on 27 September to a hot 36.2 on 28 October.

Minimum temperature

Mean daily minimum temperatures during spring 2012 were mostly near average across the Perth region, with mean daily minima mostly in the 10 °C to 14 °C range. The near average spring was the result of a near average September, an above average October, and a near average November.

Cold nights during spring were mainly observed in the second half of September, with generally clear skies and the lowest minimum of 1.0 °C recorded at Janadokot Aerodrome on the 28th. Warm nights were experienced for many sites on 10 and 17 September, between 11th to 13th October, in the latter half of November. The warmest spring night saw a minimum of 20.2 °C recorded at Champion Lakes on 22 November.

Perth Metro's mean daily minimum temperature for spring 2012 was 12.1 °C, which is above the average of 11.6 °C. Daily minima at Perth Metro in spring ranged from 3.8 °C on 28 September to 18.8 °C on 22 November.

Wind and Sunshine

Perths mean daily spring sunshine was 9.7 hours per day in 2012, which is close to the long term average of 9.3 hours per day.

Further information

Media
(03) 9669 4057
Enquiries

Extremes in spring 2012
Hottest day 36.9 °C at Pearce RAAF on 17 Nov
Warmest days on average 25.0 °C at Pearce RAAF
Coolest days on average 21.3 °C at Bickley
Coldest day 10.9 °C at Bickley on 27 Sep
Coldest night 1.0 °C at Jandakot Aero on 28 Sep
Coolest nights on average 10.2 °C at Bickley
10.2 °C at Jandakot Aero
Warmest nights on average 14.6 °C at Rottnest Island
Warmest night 20.2 °C at Champion Lakes on 22 Nov
Wettest overall 374.0 mm at Bickley
Wettest day 67.2 mm at Bickley on 4 Sep
Highest wind gust 117 km/h at Rottnest Island on 28 Nov



Record highest total spring rainfall
Total rainfall
for spring 2012 (mm)
Previous wettest
for spring
Years of
record
Average for
spring
Bickley 374.0 349.7 in 1971 43 232.8

Highest total spring rainfall for at least 10 years
Total rainfall
for spring 2012 (mm)
Most recent spring
at least this wet
Years since
wetter
Average for
spring
Jarrahdale 315.8 340.0 in 1991* 16 240.6

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




Summary statistics for spring 2012
Maximum temperatures
for spring
(°C)
Minimum temperatures
for spring
(°C)
Rainfall
for spring
(millimetres)
Mean for
spring
2012
Diff
from
average
Highest for
spring
2012
Mean for
spring
2012
Diff
from
average
Lowest for
spring
2012
Total for
spring
2012
Average
for
spring
Rank of
spring
2012
Fraction of
spring
average
Bickley 21.3 +0.2 33.4 17 Nov 10.2 +0.4 3.7 28 Sep 374.0 232.8 highest 161%
Champion Lakes 23.1   34.7 17 Nov 12.7   3.6 28 Sep 203.6
Garden Island HSF 21.8 +0.7 33.0 1 Oct 14.0 +0.4 6.7 28 Sep 121.4 116.6 average 104%
Gosnells City 24.7 +0.7 36.5 28 Oct 12.2 +0.1 3.3 28 Sep 204.9 157.0 high 131%
Jandakot Aero 23.8 +0.9 35.7 21 Nov 10.2 +0.2 1.0 28 Sep 199.4 165.0 high 121%
Medina Research Centre 24.1 +1.2 36.2 21 Nov 11.4 +0.5 2.7 29 Sep 148.8 149.8 average 99%
Pearce RAAF 25.0 +1.6 36.9 17 Nov 10.6 +0.2 2.9 24 Sep 139.4 129.3 average 108%
Perth Airport 24.2 +1.4 36.1 17 Nov 11.1 +0.5 1.9 28 Sep 202.6 143.4 high 141%
Perth Metro* 24.1 +1.0 36.2 28 Oct 12.1 +0.5 3.8 28 Sep 164.6 155.2 average 106%
Rottnest Island 21.6 +1.0 31.1 1 Oct 14.6 +0.4 8.9 28 Sep 91.8 113.5 average 81%
Swanbourne 23.8 +1.5 35.8 21 Nov 12.9 +0.4 5.3 28 Sep 164.4 150.0 average 110%

Notes

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

A Seasonal 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