Thursday 1 March 2007

CANBERRA AIRPORT MONTHLY CLIMATE SUMMARY

Hot/Dry start and a Stormy/Wet finish to summer in Canberra

Summer 2006/2007 - Main Points:

• Increased number of thunderstorms.
• Another hot summer.
• Large variability of rainfall totals throughout the ACT.
• Near record number of days of 30°C or above.

Summer 2006/2007

Rainfall: Canberra Airport  recorded a total rainfall for summer of 121.6 mm (historic average 166.7 mm) with the majority of the rain falling in February (95.2 mm). There were 20 rain days during summer which was slightly below the historic average of  23 rain days. Rainfall totals across the A.C.T. were highly variable during summer mainly due to the shower and thunderstorm activity with readings as high as 239.8 mm for Kambah. and low as 63.4 mm at Hall.

Temperatures:   The trend of above average temperatures continued during summer with Canberra experiencing an average summer temperature of 21.8°C,  more than 2°C above the historic average of 19.7°C.  This is the equal 3rd hottest summer on record with 1980/81 and 1997/98.  The hottest summer in Canberra was 22.2°C in 2005/06.

Day-time temperatures were particularly hot with the average maximum temperature of  29.5°C being the 4th highest since records commenced in 1939 (the highest was 29.9°C in 1990/91 and 2005/06).  Night time temperatures (average minimum) were also well above average at 14.3°C (historic average is 12.7°C) and the 3rd highest on record (historic average 12.4°C).  Summer had 45 hot days equal to or greater than 30°C, which is equal second highest on record with  last summer (2005/06).  The summer with the highest number of hot days was 1990/91 (51 days).   The highest temperature at Canberra Airport during summer was a scorching 40.5°C on the 12th of January (this is the third highest temperature ever recorded, the highest was 42.2°C on the 1/2/1968), while the lowest temperature was 4.8°C on the 26th of December.

Other phenomena:   Canberra had a very stormy summer, recording 20 thunderstorms (average 11) which was the equal 4th highest on record with 1969/70 (highest was 25 storms in 1960/61).  Some of the storms were severe, the most notable being the storm on 31st of December (Tuggeranong area) and the 27th of February (Central Canberra and CBD area).  Both produced large amounts of hail  with size varying in diameter from 2cm to 5cm and local flash flooding.   Sunshine during summer averaged 9.6 hours per day (average is 9.2 hours per day).   It was a little windier than usual with an average wind run of 208.9 km/day compared to the long term average of 198 km/day.  However, there was double the number of strong wind days with 10 days recorded (average 5 days). The average pressure of 1014.8 hPa was well above the average of 1012.5hPa., indicating the persistence of  high pressure systems over the ACT during summer. Evaporation was 793.2 mm well up on the average of 704.2 mm.

Canberra Airport  (Elev 578m)

Summer 2006/2007

2006/2007

Historic average

29.4

27.0

14.2

12.4

21.8

19.7

121.6

166.7

20

23

9.6

9.2

Average relative humidity at 3pm (%)

32

 38

Number of thunderstorms

20

 11

Number of windy days

10

 5

Canberra Airport

Summer 2006/2007

Highest temperature (°C) and date
Warmest day

40.5
(12th Jan)

Lowest temperature (°C) and date
Coldest night

4.8
(26th Dec)

Lowest maximum temperature (°C) and date
Coldest day

17.3
 (12th Dec)

Wettest day (mm) and date

39.0
(28th Feb)

Maximum wind gust (km/h) and date

 ENE
@ 74   (29th Dec)*

This statement has been prepared based on information available at noon on 01/03/07. Although every effort has been made to check the data, 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.

Averages: Historic average temperatures are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation. Historic rainfall averages and extremes based on the period 1939 to 2006.

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