Tuesday 3 October 2006

CANBERRA AIRPORT MONTHLY CLIMATE SUMMARY

Warmer and drier September in Canberra

September 2006 - Main Points:

• Total rain 18.2mm driest for September since 1994.
• Warm days and mild nights.
• Average maximum temperature (19.4°C) was well above average.
• Well above average sunshine.

September 2006

Rainfall:    The monthly rainfall total of 18.2mm at Canberra Airport was well below the historic September average of 53.3mm and the driest since September 1994 (when 3.0mm was recorded, the driest on record).   There were 6 rain days, well below the average of 10 rain days.  A.C.T. rainfall totals ranged from 22.2mm at Melba to 8.0mm at Mawson.

Temperatures:    The September average monthly temperature (the average of daytime and night-time temperatures) of 11.6°C was the warmest since 2001 when 11.7°C was recorded, and the third highest on record (highest 11.8°C in 1965).  The average maximum temperature at Canberra Airport was a very warm 19.4°C, well above the historic average¹ of 16.0°C and the second warmest on record (highest was 19.5°C  in 1972). There were 17 days with a maximum temperature of 20°C or greater which is the second highest on record (highest was 18 days in 1972).  Nights were generally cool to mild at Canberra Airport, the average minimum temperature of 3.9°C was 0.8°C above the historic average¹ of 3.1°C.  The highest temperature at Canberra Airport during September was 25.0°C on the 19th while the lowest was -1.1°C on the 26th.  Corresponding temperature extremes at Tuggeranong ranged from a high of 24.8°C on the 19th to a low of -1.8°C on the 12th.

Other phenomena:   Canberra had plentiful sunshine during September with an average of 9.2 hours per day, the 3rd highest ever recorded in September (historic average 7.5 hrs/day, records since 1978).  There was 1 thunderstorm (average 2) with 1 hail day (average 0).  There were 14 frosts during the month compared with an historic average of 13 frosts.  Canberra Airport reported 2 fogs (average 3).  It was a little less windy than usual with an average wind run of 221 km per day (historic average 225 km/day), with 4 strong wind days (average 4). Air pressure was well above average at 1021.6 hPa (historic average 1017.3 hPa) and the highest since 1990, indicative of the persistence of high pressure systems over Canberra and southern NSW during September. Evaporation for the month was 151.2 mm well above the average of  112.3 mm and the highest since 1994.

Canberra Airport  (Elev 578m)

September 2006

Historic average¹

September 2005

19.4

 15.9

 16.3

3.9

 3.2

 4.6

11.6

 9.5

 10.5

 18.2

53.3#

 100.6

 6

 10

 14

 9.2

 7.5

 7.0

Average relative humidity at 3pm (%)

 36

 50

 57

Number of thunderstorms

 1

 2

 3

Number of windy days*

 4

 4

 3

Number of frosts

 14

13

10

Tuggeranong  (Elev 587m)

September 2006

Historic average #

September 2005

19.3

 17.4

 16.4

 3.8

 4.2

 4.4

 11.5

 10.8

 10.4

 10.8

 72.1

 83.4

 4

 10

 13

September 2006

All years

September 2006

All years #

September 2006+

All years*

25.0
19th

 28.6
(1965)

24.8
19th

26.4
(1998)

 16.0
(19th)

17.0
(2005)

 -1.1
26th

-6.4
(1982)

 -1.8
12th

-4.2
(2002)

 -6.0
(25th)

-6.5
(2004)

 11.2
6th

5.9
(1959)

10.2
6th

9.1
(1996)

 7.0
(11th)

-1.0
(2005)

 10.4
4th

43.4
(1978)

 5.6
7th

37.0
(1999)

39.0
(2005)

 N
@ 91
24th

NNW
@ 108
(1972)

 N
@76
24th

 NW
@ 59
(2005)

 n/a

  N
@ 98
(2004)

This statement has been prepared based on information available at noon on 03/10/06. Although every effort has been made to check the data, it is possible that results in September 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.  Historic rainfall averages and extremes for Canberra Airport are based on all years of record 1939 - 2005.

Further information: Contact: Owen Offler on 02 62470411 or 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 Australian Capital Territory localities are available here