Monday, 3 December 2007 - Seasonal Climate Summary for Canberra area - Product code IDCKGC2xx0

Canberra has equal warmest spring nights on record

Summary

  • warm days, 5th highest average maximum temperature on record
  • 4 consecutive springs with above average maximum temperatures
  • 54 days exceeded 20°C (normally only 38 days exceeding 20°C)
  • warm nights, equal highest average minimum temperature on record (7.8°C or 1.8°C above average and same as 2005)
  • 13 consecutive springs with above average minimum temperatures
  • 7 nights with minimum temperature above 15°C, the highest on record (normally only 1 night above 15°C)
  • below average rainfall
  • plentiful sunshine

Rainfall

The total spring rainfall of 131.2 mm at Canberra Airport was below the historic spring average1 of 178.8 mm.   Most of this spring's rainfall occurred during November (94.0 mm) with September and October being mostly dry months.  This could be attributed to a delayed rainfall response of the La Nina event established since August in the Pacific Ocean. There were 28 rain days, which is slightly below the historic average of 30 rain days.   The highest spring rainfall totals were in western parts of the ACT while central Canberra recorded the lowest falls. Totals ranged from a high of 255.0 mm at Mount Ginini AWS to a low of 112.7 mm at Curtin. The highest suburban total was 183.0 mm at Tuggeranong AWS.

Temperatures

Average maximum temperatures during spring were well above the historic average.  The average maximum (daytime) temperature at Canberra Airport was 21.8°C, which is the 5th warmest average maximum temperature on record for spring and 2.5°C above the historic average1 of 19.3°C.  An abundance of warm, sunny days with below average rainfall contributed towards the warm conditions. For example there were 54 days when the temperature exceeded 20°C in spring compared to the historic average of 38 days over 20°C. Conditions were significantly cooler in the elevated southern mountain regions of the ACT where the average maximum temperatures at Mount Ginini (elev 1760 m) was 12.4°C for the spring period.

This is the 4th consecutive spring with above average maximum temperatures in Canberra with 7 of the last 8 springs recording above average maximum temperatures.

Average minimum (night-time) temperatures over Canberra were well above the historic spring average. The average minimum temperature at Canberra Airport of 7.8°C was 1.8°C above the historic spring average1 and ranking equal highest on record, and the same as 2005. Canberra experienced a distinct lack of cold nights this spring with only 27 nights falling below 5°C. Normally Canberra would expect around 39 nights below 5°C during spring.

Canberra has now experienced 13 consecutive springs with above average minimum temperatures.

Extremes of temperature across Canberra during spring ranged from a high of 33.4°C at Canberra Airport on 20 and 21 November to a low of −2.5°C at Tuggeranong AWS on 16 and 23 September. In the elevated regions of the ACT the corresponding extremes at Mount Ginini (elev 1760 m) ranged from a high of 24.9°C on 20 November to a low of −5.8°C on 4 September.

Other phenomena

Canberra Airport recorded 20 frosts during spring compared to the historic average of 22 frosts. There was only 2 fogs recorded at the airport, both in September (average 7 fogs).  It was generally a very sunny spring with sunshine averaging 8.9 hours per day (historic average 8.4 hours per day).  The season was a little windier than usual with 12 strong wind days (average 10) and 1 gale day. The gale occurred on 3 October with tree damage reported in several ACT suburbs. The average wind run was 211 km per day, very close to the historic spring average of 216 km per day.

During spring, there were 11 thunderstorms (average 8) and one hail day (on 26 October) (average 3 hail days) reported at Canberra Airport. The average air pressure of 1016.2 hPA was slightly above the long term average of 1015.3 hPa. Because of the above average temperatures and below average humidity during spring, the evaporation rate has been higher than normal in Canberra with a total of 536 mm compared to the historic average of 467 mm.

Further information

Mike De Salis
Climate Information Officer
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email mikede@bom.gov.au

Extremes for the ACT

Hottest day
Highest temperature
33.4°C at Canberra Airport on 20 Nov and 21 Nov
33.4°C at Tuggeranong AWS on 20 Nov
Warmest days on average
Highest mean daily maximum temperature
21.8°C at Canberra Airport
Coolest days on average
Lowest mean daily maximum temperature

21.7°C at Tuggeranong AWS
12.4°C at Mount Ginini AWS

Coldest day
Lowest daily maximum temperature
11.9°C at Tuggeranong AWS on 5 Sep
2.0°C at Mount Ginini on 5 and 11 Sep
Coldest night
Lowest temperature
−2.5°C at Tuggeranong AWS on 16 Sep and 23 Sep
−5.8°C at Mount Ginini on 4 Sep
Coolest nights on average
Lowest mean daily minimum temperature
7.1°C at Tuggeranong AWS
3.3°C at Mount Ginini AWS
Warmest nights on average
Highest mean daily minimum temperature
7.8°C at Canberra Airport
Warmest night
Highest daily minimum temperature
16.4°C at Canberra Airport on 22 Nov
Wettest overall
Highest total rainfall

188.6 mm at Tharwa
255.0 mm at Mount Ginini AWS

Driest overall
Lowest total rainfall
112.8 mm at Curtin
Wettest day
Highest daily rainfall
43.6 mm at Sullivan Creek (Southwell) on 4 Nov
Highest wind gust
94 km/h at Canberra Airport on 3 Oct
104 km/h at Mount Ginini on 1 Oct

Summaries for the ACT

Summary statistics for spring 2007
Maximum temperatures
for spring
(°C)
Minimum temperatures
for spring
(°C)
Rainfall
for spring
(millimetres)
Mean for
spring
2007
Diff
from
normal
Highest for
spring
2007
Mean for
spring
2007
Diff
from
normal
Lowest for
spring
2007
Total for
spring
2007
Normal
for
spring
Rank of
spring
2007
Fraction of
spring
normal
Canberra Airport 21.8 +2.5 33.4 21 Nov 7.8 +1.8 −2.3 16 Sep 131.2
178.8
low 73%
Tuggeranong 21.7 +1.1 33.4 20 Nov 7.1 +0.6 −2.5 16 Sep 183.0
174.8
normal 105%
Mount Ginini* 12.4   24.9 20 Nov 3.3   −5.8 4 Sep 255.0
-

* new station, historic averages not available


Notes

This statement has been prepared based on information available at 2 pm on Monday 3 December 2007. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Averages:  historic average temperatures for Canberra Airport are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation. The historic average temperatures for Tuggeranong AWS are based on all available records 1996−2007. Rainfall averages at Canberra Airport are based on all years of record 1939−2007.

Normals 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 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of "normal" 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, normal in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of normal shows how much rain has fallen this time as a percentage of the long-term mean.