Tuesday 4 July 2006

A.C.T. MONTHLY CLIMATE SUMMARY - CANBERRA METEOROLOGICAL OFFICE

Canberra has cold, frosty start to winter

June 2006 - Main Points:

• Coldest average daytime maximum temperature since 1993.
• 21 frosts - highest since 1999.
• 7 consecutive heavy frosts (temperature below –2°C from 12th to 18th) - longest such spell in June since 1984.
• On 15th, maximum temperature (5.9°C) lowest for June since 1983.
• Wettest June since 1998, total of 74.0mm.

Temperatures:   In a marked change from recent months, Canberra has experienced significantly below average temperatures.   The average monthly mean temperature (the average of daytime and night-time temperatures) of 5.9°C was 0.5°C below the historic average¹ of 6.4°C, ending the run of  5 consecutive Junes with above average temperatures. Days were cool to cold with the average maximum day-time temperature of 11.9°C being below the historic average of 12.2°C and the lowest since 1993 (when 11.7°C). A notable cold day was 15th June, a day of fog and low cloud, when the mercury struggled to a maximum temperature of only 5.9°C, the coldest June maximum since 1983 and the coldest 15th June maximum since 1958 (when 7.7°C).

Nights were also cold with an average minimum temperature at Canberra Airport of –0.2°C, about one degree below the historic average (of 0.7°C) and the lowest for 6 years.  Frosts (minimum temperature 2°C or less) were common, Canberra Airport recording 21 frosts, three more than the historic average. A particularly heavy frost spell occurred from 12th to 18th when minimum temperatures were less than –2.0°C on 7 consecutive nights.  This is the longest such spell in June since a similar spell in 1984.  On the 28th the minimum temperature of  –5.3°C was the lowest temperature at Canberra Airport since 21st July 2004 when it fell to –7.3°C.  The lowest temperature recorded at Tuggeranong was –6.3°C on the 14th.

Rainfall:   Canberra Airport's total June rainfall of 74.0mm was well above the historic average of 39.7mm and the wettest June since 1998 (when 117.4mm was recorded). The majority of the rainfall fell on 2 days (the 2nd with 24.0mm and the 11th with 30.6mm). There were 10 rain days during the month (historic average 9 days). Rainfall across the ACT varied only slightly and ranged from 83mm at Gungahlin to 61mm at Tidbinbilla Nature Reserve.

Other phenomena:  There were 8 fog days compared to an historic average of 7 days. The fog on the 15th persisted until after midday resulting in the coldest maximum temperature for June 2006 of 5.9°C and delaying air traffic at Canberra Airport. It was less windy than usual during June with a wind run of 99km/day (historic average 171km/day) with 1 strong wind day (historic average 2 days).

Canberra Airport  (Elev 578m)

June 2006

Historic average

June 2005

Average maximum
temperature (°C)

 11.9

12.2

14.1

Average minimum
temperature (°C)

 –0.2

0.7

2.3

Mean temperature (°C)

5.9

6.4

8.2

Monthly rainfall (mm)

74.0

39.8#

73.0

Number of rain days

10

9

13

Average daily
sunshine (hours)

5.6

5.2

4.6

Average relative humidity at 3pm (%)

59

60

60

Number of thunserstorms

0

0

0

Number of windy days*

 1

2

0

June 2006

All years

June 2006

 16.1  (20th)

  20.1  (1957)

 15.4  (8th)

 –5.3   (28th)

  –8.5  (1957)

 –6.3  (14th)

5.9  (15th)

   2.1  (1949)

  4.8  (15th)

 31.6   (11th)

54.6  (1997)

 33.0  (11th)

S @ 68  (11th)

W @ 96  (1975)

S @ 65  (11th)

This statement has been prepared based on information available at noon on 04/07/06. Although every effort has been made to check them, it is possible that results may change as new information becomes available.

A note about deciles: Deciles are used to give an element (in this case rainfall or temperature) a ranking. Deciles are calculated by arranging the totals in ascending order (from lowest to highest) then splitting them into 10 equal groups (thus the groups are called deciles). The first group would be in decile range one, the second group in decile range two, etc up to the highest annual totals (highest 10 per cent) being in decile range 10.

¹Averages:  Historic average temperatures for Canberra Airport are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation.

Further information: Contact Owen Offler 02 6247 0411, email: climate.act@bom.gov.au

A directory of Bureau services is available on poll fax: 1800 630 100

The latest rainfall and temperature maps are available here
Climate averages for New South Wales localities are available here
Daily Weather Observations for selected New South Wales localities are available here