Tuesday, 1 May 2007 - Monthly Climate Summary for Canberra rainfall extremes - Product code IDCKGC1xx0

Canberra has warm April with welcome late rain

Summary

  • Warm month with above average temperatures
  • Sunnier than normal
  • Below average rainfall but wettest April since 2000

Rainfall

Canberra Airport received a total of 27.6 mm of rainfall during April, which is the wettest April since 2000 when 61.8 mm was recorded.  Although it was below the historic average 46.7 mm it was still within the normal variability of rainfall.  There were 5 rain days which is below the historic average of 7 rain days. Most of the rain fell over the last few days of the month when a low-pressure system and associated north-west cloud band brought widespread rain to the region followed by showers.  No rain fell at Canberra Airport during the first 23 days of the month, the 4th longest rainless spell on record for April. There was a moderate variation in April rainfall across the ACT with the lowest totals recorded in the north and the highest in the west. April totals ranged from 56.6 mm at Stirling (Weston Creek) to 24.8 mm at Ginninderra.

Temperature

Generally warm conditions prevailed in Canberra throughout April, except for the last 8 days when maximum temperatures were all below average. The average mean temperature (the average of daytime and night-time temperatures) was 14.9°C, well above the historic average1 of 13.3°C. The average maximum temperature at Canberra Airport was 22.1°C or 2.2°C above the historic average1 of 19.9°C. Canberra generally experienced mild nights during April with an average minimum temperature of 7.8°C, well above the historic average1 of 6.8°C.

Extremes of temperature at Canberra Airport ranged from a high of 26.5°C on the 15th to a low of 3.6°C on the 20th.  Corresponding extremes at Tuggeranong ranged from 27.4°C on the 15th to a low of 2.9°C on the 26th.

Other phenomena

There were no thunderstorms recorded during April (historic average 1). Average sunshine for April was 7.6 hours per day, slightly above the historic average of 7.3 hours per day.  Generally light winds prevailed in Canberra during April which is fairly typical of Autumn. The wind run was 133km per day, well below the historic average wind run of 150 km per day and no strong wind days were recorded during the month (average 1).  There were 3 fogs recorded at Canberra Airport (historic average 3). These occurred on the 5th, 10th and 21st with visibility as low as 700 metres on the 5th.  Fog patches were also recorded on the 9th, 12th, 17th and 21st.   Air pressure was above average at 1021.0 hPa (historic average 1019.5hPa).  The total evaporation of 108.8 mm was close to the historic average evaporation of 109.4 mm.

Further information

Owen Offler
ACT Climate Services Centre
Bureau of Meteorology
Phone (02) 6247 0411
Email:   climate.act@bom.gov.au

Extremes for the ACT

Hottest day
Highest temperature
27.4°C at Tuggeranong on the 15th
Warmest days on average
Highest mean daily maximum temperature
22.1°C at Canberra Airport
Coolest days on average
Lowest mean daily maximum temperature
22.0°C at Tuggeranong
Coldest day
Lowest daily maximum temperature
15.9°C at Tuggeranong on the 24th
Coldest night
Lowest temperature
1.0°C at Mount Ginini on the 25th
2.9°C at Tuggeranong on the 26th
Coolest nights on average
Lowest mean daily minimum temperature
7.6°C at Tuggeranong
Warmest nights on average
Highest mean daily minimum temperature
7.8°C at Canberra Airport
Warmest night
Highest daily minimum temperature
14.8°C at Canberra Airport on the 4th
Wettest overall
Highest total rainfall
56.6 mm at Stirling (Weston Creek)
Driest overall
Lowest total rainfall
24.8 mm at Ginninderra
Wettest day
Highest daily rainfall
26.2 mm at Canberra Botanic Gardens on the 28th
Highest wind gust
52 km/h at Tuggeranong on the 20th

Summaries for Canberra area

 In the following table, certain key sites have been highlighted to make them easier to identify.

Summary statistics for the Canberra area for April 2007
Maximum temperatures
for April
(°C)
Minimum temperatures
for April
(°C)
Rainfall
for April
(millimetres)
Mean for
April
2007
Diff
from
normal
Highest for
April
2007
Mean for
April
2007
Diff
from
normal
Lowest for
April
2007
Total for
April
2007
Normal
for
April
Rank of
April
2007
Fraction of
April
normal
Canberra Airport 22.1 +2.2 26.5 15th 7.8 +1.0 3.6 20th 27.6 46.4 normal 59%
Tuggeranong* 22.0 +0.6 27.4 15th 7.6 +1.0 2.9 26th 34.0 24.5 normal 139%

*  new station, historic average based on short period 1996 - 2006 only.

Summary phenomena for Canberra Airport for April
 

April 2007

Normal for April

Number of rain days

 5

 7

Average sunshine hours per day

 7.6

7.3

Average humidity at 3pm (%)

40

46

Number of thunderstorms

 0

1

Number of windy days

 0

 1

Number of frosts

0

5


Notes

This statement has been prepared based on information available at 2 pm on Tuesday 1 May 2007. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

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.