Thursday, 1 November 2012 - Monthly Climate Summary for Canberra - Product code IDCKGC25R0
Canberra in October 2012: A warm, sunny October but snow in the ACT
- Coldest October nights on record.
- Coldest October day since 1968, but above average maximum temperatures.
- Wettest October event since 1976.
Rainfall - Wettest event since 1976, fewest rain days since 2006
Canberra Airport recorded 66 mm of rain during October, close to the historical average of 62.4 mm. The rain fell over five days, half the October average and the fewest rain days since 2006.
Almost all of the rain recorded during the month was associated with a surface trough and East Coast Low that developed off the south coast of NSW over the 11th and 12th. Canberra Airport recorded a 48 hour total of 56.2 mm to 9am on the 12th, the wettest October event since 83.8 mm fell over two days in October 1976 and the wettest event for any month since March this year.
Temperature - Generally warm days and very cold nights
Canberra Airport recorded an average maximum temperature of 20.8 °C during October, 1.4 °C above the historical average and the warmest since 2008. Seven days reached at least 25 °C (average 3 days), with 18 days reaching at least 20 °C, the most warm days since 2008 (average 13 days). The generally warm days were associated with clear conditions during most of the month and relatively few rain days.
Only one day during the month dropped below 14 °C, with a maximum temperature of just 8.6 °C on the 11th associated with a rain event and very cold southerly air. This is the coldest October day since just 8.2 °C was recorded on October 1 1968, and the third coldest day since records began in 1939.
Minimum temperatures during October averaged just 3.4 °C, 2.7 °C below the historical average and the coldest October on record. The cool nights were associated with the generally clear conditions during the month, an increased frequency of southerly winds, and a lack of warm nights. Only nine nights were warmer than 5 °C, half the historical average and the fewest mild nights on record, while five nights dropped to 0 °C or lower, the equal highest on record with October 1971. The coldest night fell on the 1st, reaching -2.2 °C at the airport, the coldest October night since 1993.
Other phenomena - Snow in the ACT
An East Coast Low on the south coast of NSW was the major feature of the month, bringing heavy rain and very cold temperatures to Canberra on the 11th and 12th as well as reports of snow across the ACT; in nearby Goulburn this was the first report of spring snow since 22 November 1996.
The prevailing wind direction during October was northwesterly, with 66% of 3pm winds between NNW and WNW. Morning winds were predominantly southerly, with 43% of 9am winds S-SE, well above the historical frequency. There were two strong wind days, with a maximum wind gust of 93 km/hr as a strong cold front crossed the state on the 16th.
|Extremes in October 2012|
29.7 °C at Tuggeranong (Isabella Plains) AWS on the 31st|
|Warmest days on average||
20.9 °C at Tuggeranong (Isabella Plains) AWS|
|Coolest days on average||
12.7 °C at Mount Ginini AWS|
0.5 °C at Mount Ginini AWS on the 11th|
-4.5 °C at Mount Ginini AWS on the 7th|
|Coolest nights on average||
2.1 °C at Mount Ginini AWS|
|Warmest nights on average||
4.1 °C at Tuggeranong (Isabella Plains) AWS|
11.1 °C at Canberra Airport on the 6th|
|Warmest on average overall||
12.5 °C at Tuggeranong (Isabella Plains) AWS|
|Coolest on average overall||
7.4 °C at Mount Ginini AWS|
72.4 mm at Nicholls (Gungahlin Lakes)|
33.0 mm at Canberra Airport on the 12th|
|Highest wind gust||
93 km/h at Canberra Airport on the 16th|
|Summary statistics for October 2012|
|Mount Ginini AWS||12.7||20.2||31st||2.1||-4.5||7th||44.6|
|Tuggeranong (Isabella Plains) AWS||20.9||29.7||31st||4.1||-1.5||1st||58.6|
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 (all years of record).
A Monthly 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 10 am on Thursday 1 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 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.