Friday, 1 June 2012 - Seasonal Climate Summary for ACT - Product code IDCKGC25R0
Canberra in autumn 2012: Wettest autumn since 1989
- Wettest Autumn since 1989, 8th wettest on record.
- 3rd wettest 4 day period on record for any season.
- 12th driest April-May period on record.
- Below average temperatures, coldest autumn since 1984.
Canberra Airport recorded 231.3 mm of rain during autumn, well above the historical average of 141.2 mm. This is the wettest autumn since 477.8 mm was recorded in 1989, and the 8th wettest autumn on record for Canberra. Most of the rain fell during the first week of March, with 152.8 mm between the 1st and 4th associated with a deep low pressure trough that brought widespread heavy rain to eastern Australia. This is only the third event for any month to record more than 150 mm over 4 days at Canberra, following events in March 1950 and March 1989.
The remainder of autumn was generally dry, with both April and May recording less than half their historical average, the 12th driest April-May total on record. There were consequently only 11 days with at least 2 mm of rain during the season, normal for autumn, but two days above 50 mm, the equal highest on record and most since 1989. Interestingly, six of the eleven drier April-May periods have occurred since 2000.
The average maximum temperature at Canberra Airport was 19.3 °C during autumn, slightly below the historical average of 20 °C. This is also slightly cooler than autumn 2011, and the coolest autumn since 1995. Both 2011 and 2012 had below average temperatures during autumn, which is normal for autumns following La Niña events. Temperatures were coldest during March, which was the 5th coldest on record for Canberra associated with wet and cloudy conditions, with close to normal temperatures during April and May, including the warmest start to April since 1998.
The average minimum temperature during autumn was 5.3 °C, 1.5 °C below the historical average. This is the equal 4th coldest autumn on record for Canberra, and the coldest since 5.3 °C was recorded in 1966. Nights were below average throughout the season, but particularly cold during May, which was the coldest since 1961. Twenty nights were 0 °C or lower during the season, the 4th highest on record although slightly fewer than autumn 2011 (21 nights), associated with generally clear overnight conditions.
The average temperature for Canberra Airport during autumn was consequently 12.3 °C, the equal 4th coldest autumn on record and the coldest since 12.3 °C in autumn 1984.
The prevailing wind direction during autumn was N-WNW, forming 66% of 3pm winds. There were 7 strong wind days reported at the airport, with the strongest gust anywhere in the ACT reaching 81 km/hr at Mt Ginini on 23 March.
Canberra Airport recorded an average of 6.5 hours of bright sunshine during autumn, below the autumn average of 7.1 hours. There were 7 thunderstorms reported in the ACT, with 13 frosts and 19 fogs reported at the airport.
|Extremes in autumn 2012|
27.3 °C at Tuggeranong (Isabella Plains) AWS on 14 Mar|
|Warmest days on average||
19.3 °C at Canberra Airport|
19.3 °C at Tuggeranong (Isabella Plains) AWS
|Coolest days on average||
11.0 °C at Mount Ginini AWS|
2.3 °C at Mount Ginini AWS on 24 Apr|
-5.0 °C at Canberra Airport on 19 May|
|Coolest nights on average||
3.4 °C at Mount Ginini AWS|
|Warmest nights on average||
6.4 °C at Tidbinbilla Nature Reserve|
15.8 °C at Tuggeranong (Isabella Plains) AWS on 17 Mar|
|Warmest on average overall||
12.5 °C at Tuggeranong (Isabella Plains) AWS|
|Coolest on average overall||
7.2 °C at Mount Ginini AWS|
454.0 mm at Mount Ginini AWS|
107.6 mm at Mount Ginini AWS on 4 Mar|
|Highest wind gust||
81 km/h at Mount Ginini AWS on 23 Mar|
|Summary statistics for autumn 2012|
|Canberra Airport||19.3||-0.7||27.2||14 Mar||5.3||-1.5||-5.0||19 May||231.3||141.2||v high||164%|
|Mount Ginini AWS||11.0||19.5||3 Apr||3.4||-4.5||10 Apr||454.0|
|Tidbinbilla Nature Reserve||18.5||-0.9||25.5||31 Mar||6.4||-0.4||-3.2||7 May||149.9||196.0||average||76%|
|Tuggeranong (Isabella Plains) AWS||19.3||27.3||14 Mar||5.7||-4.5||22 May||343.0|
As of March 2010, the official station for Canberra is 70351 'Canberra Airport'. Averages from the previous site, 70014 Canberra Airport Comparison, are used for comparisons.
A Seasonal Climate Summary is prepared to list the main features of the weather in ACT Monthly Summary 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 11 am on Friday 1 June 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 20 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
(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.