Wednesday, 1 June 2011 - Monthly Climate Summary for ACT Monthly Summary - Product code IDCKGC25R0

ACT in May 2011: Coldest nights in 50 years

  • 4th coldest May on record for minimum temperatures
  • Coldest May maximum temperatures since 2000
  • Below average rainfall

Extremes Records Summaries Important notes the top

Rainfall

Canberra Airport recorded just 12 mm of rain during May, well below the historical average of 44.4 mm although substantially wetter than May 2009 (2.4 mm). The rain fell over three days, well below the May average of 8 days. Only one of these exceeded 0.2 mm, when the passage of a cold front brought 11.6 mm at the Airport on the 23rd. In comparison, Mt Ginini recorded 72.2 mm during the month, including 60 mm between the 23rd and 24th associated with the same event.

Temperature

The average maximum temperature at Canberra Airport during May was 15.8 °C, slightly above the historical average of 15.5 °C, associated with generally clear conditions during the month. However, this is the coolest May since 15.1 °C was recorded in May 2000, reflecting the generally warm temperatures during the past decade.

In comparison, minimum temperatures averaged just 0 °C during May, 3.2 °C below the historical average. This is the 4th coldest May on record for minimum temperatures, and the coldest since -0.5 °C was recorded in 1961. Temperatures below zero were recorded 19 times during May, the second highest frequency on record, following 27 below zero days in May 1957. This included a minimum temperature of -6.9 on the 15th, the third coldest May night on record and the coldest since 1976, in addition to the equal 4th coldest May night on the 16th (-6.5 °C). The cool minimums were associated with generally clear conditions and persistent westerly winds during the month, which drove cool dry air into the state.

Wind

Winds were generally northwesterly during May, forming 48% of 3pm winds, slightly above average for this time of year. The windiest day at the Airport was the 11th, with a maximum wind gust of 69 km/hr.

Other phenomena

Canberra Airport recorded an average of 6.7 hours of sunshine during May, slightly above the historical average of 6.0 sunshine hours. No thunderstorms were reported at the Airport, with one thunderstorm reported in the ACT on the 2nd.

Further information

NSW Climate Services Centre
NSW Regional Office
Bureau of Meteorology
Phone (02) 9296 1555
Email climate.nsw@bom.gov.au
Extremes in May 2011
Hottest day 20.9 °C at Canberra Airport on the 1st
Warmest days on average 15.8 °C at Canberra Airport
Coolest days on average 6.6 °C at Mount Ginini AWS
Coldest day -3.1 °C at Mount Ginini AWS on the 11th
Coldest night -6.9 °C at Canberra Airport on the 15th
Coolest nights on average -0.1 °C at Mount Ginini AWS
Warmest nights on average 1.8 °C at Tidbinbilla Nature Reserve
Warmest night 11.0 °C at Tuggeranong (Isabella Plains) AWS on the 2nd
Warmest on average overall 8.1 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 3.3 °C at Mount Ginini AWS
Wettest overall 72.2 mm at Mount Ginini AWS
Wettest day 31.4 mm at Mount Ginini AWS on the 24th
Highest wind gust 80 km/h at Mount Ginini AWS on the 13th

Extremes Records Summaries Important notes the top


Summary statistics for May 2011
Maximum temperatures
for May
(°C)		 Minimum temperatures
for May
(°C)		 Rainfall
for May
(millimetres)
Mean for
May
2011		 Diff
from
average		 Highest for
May
2011		 Mean for
May
2011		 Diff
from
average		 Lowest for
May
2011		 Total for
May
2011		 Average
for
May		 Rank of
May
2011		 Fraction of
May
average
Canberra Airport 15.8 +0.3 20.9 1st 0.0 -3.2 -6.9 15th 12.0 44.4 low 27%
Mount Ginini AWS 6.6   11.5 1st -0.1   -6.4 12th 72.2
Tidbinbilla Nature Reserve 14.9 -0.4 19.8 1st 1.8 -2.0 -3.9 15th 44.6 66.0 average 68%
Tuggeranong (Isabella Plains) AWS 15.3   20.8 1st 0.8   -5.7 15th 24.6

Extremes Records Summaries Important notes the top

Notes

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 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 Wednesday 1 June 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 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 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

Climate Officer
NSW Climate Services Centre
NSW Regional Office
Bureau of Meteorology
Phone (02) 9296 1555
Email climate.nsw@bom.gov.au