Thursday 1 May 2008 - Monthly Climate Summary for Canberra - Product code IDCKGC1xx0

A cool end to April in Canberra

Summary

  • Close to average maximum temperatures, cooler than average minimum temperatures
  • Below average rainfall
  • Cold and snowy end to the month

Rainfall

Canberra Airport recorded a total rainfall of only 17.4 mm during April, which is well below the historical average1 of 46.4 mm, falling within decile 3. There were only 5 rain days during the month, compared to the historic average of 7 days. Monthly totals around the ACT ranged from a high of 41.4 mm at Mount Ginini AWS, to a low of 8.2 mm at Torrens (Darke St).

The month of April was characterised by persistent high pressure over the region. Rainfall was below average over the whole ACT region due to this stable pattern. Nearly all of Canberra's rainfall during April occurred due to the passage of cold fronts on the 2nd, 12th/13th, and on the 26th/27th. The last of these fronts was particularly vigorous, with snow reported on the Brindabella's behind the change.

Temperatures

Close to average temperatures prevailed over the ACT during April. The mean maximum temperature for Canberra Airport was 19.5 ºC, which is just below the historical average2 of 19.9 °C. The highest temperature in the ACT was 24.1 °C at both Canberra Airport and Tuggeranong on the 12th. A cold spell towards the end of the month saw maximum temperatures drop to 11.3 °C on the 28th at Canberra Airport, the coldest April day since 1999 (11.3 °C on the 27th) . It reached a maximum of only -2.0 °C at Mt Ginini (elevation 1760 m) on the same day.

The average minimum temperature at Canberra Airport was 5.2 ºC, cooler than the historical average of 6.8 ºC. On the 29th, the temperature dropped to -2.1 °C at the Airport. Colder April conditions were experienced in 2006, where the minimum temperature reached -3.4 °C (on the 22nd). The coldest conditions recorded in the ACT in April was at Mt Ginini, where the minimum temperature dropped to -5.0 ºC.

The mean temperature (average of maximum and minimum temperature) was 12.3 °C, well below the historical average of 13.4 °C.

Wind

The prevailing direction over the ACT during the mornings (9am) was from the south to southeast, observed around 70% of the time. This is significantly higher than the normal frequency from these directions at this time. However, during the afternoon the wind was similar to long term conditions, with the prevailing wind direction being from the northwest about 33% of the time. The highest wind gust recorded was 83 km/hr at Canberra Airport on the 2nd, associated with the passage of a cold front.

Other phenomena

Canberra averaged 8 hours of sunshine per day, which is above the historical average of 7.3 hours. There was one thunderstorm reported at Canberra Airport during April on the 13th (historical average 1.2), and one day with hail on the 27th.

Further information

Louise Garbers
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email reqnsw@bom.gov.au

Extremes for the ACT

Hottest day
Highest temperature
24.1 °C at Canberra Airport on the 12th
24.1 °C at Tuggeranong (Isabella Plains) AWS on the 12th
Warmest days on average
Highest mean daily maximum temperature
19.6 °C at Tuggeranong (Isabella Plains) AWS
Coolest days on average
Lowest mean daily maximum temperature
10.5 °C at Mount Ginini AWS
Coldest day
Lowest daily maximum temperature

-2.0 °C at Mount Ginini AWS on the 28th

Coldest night
Lowest temperature
-5.0 °C at Mount Ginini AWS on the 29th
Coolest nights on average
Lowest mean daily minimum temperature
2.0 °C at Mount Ginini AWS
Warmest nights on average
Highest mean daily minimum temperature
5.2 °C at Canberra Airport
Warmest night
Highest daily minimum temperature
9.4 °C at Tuggeranong (Isabella Plains) AWS on the 18th
Wettest overall
Highest total rainfall
41.4 mm at Mount Ginini AWS
Wettest day
Highest daily rainfall
18.2 mm at Canberra (Corin Dam (Boat Ramp)) on the 3rd
Highest wind gust
83 km/h at Canberra Airport on the 2nd

Records

Record lowest April daily maximum temperature
Lowest daily maximum
temperature
in April 2008 (°C)
Previous lowest
for April
Years of
record
Normal for
April
Tidbinbilla Nature Reserve 5.0 on the 27th 8.0 on the 7th in 1995 23 19.1



Summaries for the ACT

Summary statistics for April 2008
Maximum temperatures
for April
(°C)
Minimum temperatures
for April
(°C)
Rainfall
for April
(millimetres)
Mean for
April
2008
Diff
from
normal
Highest for
April
2008
Mean for
April
2008
Diff
from
normal
Lowest for
April
2008
Total for
April
2008
Normal
for
April
Rank of
April
2008
Fraction of
April
normal
Canberra Airport 19.5 -0.5 24.1 12th 5.2 -1.5 -2.1 29th 17.4 46.0 low 38%
Tuggeranong* 19.6 -1.8 24.1 12th 4.4 -2.3 -3.0 30th 11.4 23.4 normal 49%

* historic averages for Tuggeranong based on short period 1996-2007.


Notes

This statement has been prepared based on information available at 11am Thursday 1 May 2008. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Historic rainfall averages for Canberra Airport are based on all years of record 1939 - 2008.

2Historic average temperatures for Canberra Airport are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation.  

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.

Further information

NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email reqnsw@bom.gov.au