Tuesday, 4 November 2008 - Monthly Climate Summary for ACT - Product code IDCKGC15R0

ACT has another warm, dry and sunny October

Summary

  • 9th consecutive October with below average rainfall
  • 3rd warmest maximum temperatures (behind 2006 & 2007) at the Airport site
  • Warmer than average minimum temperatures
  • Plentiful sunshine during October

Rainfall

Canberra Airport recorded a total rainfall of 33.2 mm during the month, which is well below the historical average1 of 62.7 mm. The dry conditions continue the recent trend of low October rainfall in Canberra with now 9 consecutive Octobers having below average rainfall. Prevailing high pressure systems dominated the Tasman Sea, NSW and the ACT during October maintaining generally settled and sunny weather in the Canberra region.

Much of the rainfall was due to thunderstorm activity on the 6th, 13th and 14th associated with the passage of low pressure troughs. The extreme northern parts of the ACT scored the highest totals for the month with Hall, on the border with NSW, receiving 39 mm. There were 7 rain days, compared to the average of 10. The wettest day was 13.4 mm at Canberra Airport on the 14th, which was due to 2 separate storms late on 13th and early 14th. On the same day, Hall received the ACT's highest daily rainfall for the month of 21.2 mm.

See a map of total rainfall for the ACT and surrounding region. See a NSW map of rainfall deciles.

Temperatures

The typical Spring pattern of variable temperatures persisted in the ACT throughout the month of October. Maximum temperatures at Canberra Airport varied from a low of 15°C on the 22nd, to a high of 30.7°C on the 27th. This was also the warmest day recorded throughout the ACT for the month of October. Overall, the mean maximum temperature at Canberra Airport was 23.0°C, which is 3.6°C above the historical average of 19.4°C. This is the 3rd highest October on record, behind 2007 (23.2°C) and 2006 (24.2°C). The high frequency of north to northwesterly winds combined with the sunny conditions in Canberra during October would have contributed to these warmer temperatures.

Nights were also above average with the mean minimum temperature for the month being 7.2°C compared to the average of 6.0°C. At Canberra Airport, minimum temperatures ranged from a frosty 0.3°C on the 7th to a warm 16.8°C on the 3rd. The lowest temperature in the Canberra metropolitan area was −0.5°C at Tuggeranong on the 7th. A total of 5 frosts were reported during the month, just below the October average of 7 frosts. The coldest nights were experienced at higher elevations of the ACT with Mount Ginini (elev 1760 m) recording a minimum of −4.8°C on both the 7th and 22nd, the lowest temperature in October at that site in the 4 years of record.

See NSW map of mean maximum temperatures. See NSW map of maximum temperature anomalies.

See NSW map of mean minimum temperatures. See NSW map of minimum temperature anomalies.

Wind

The prevailing wind direction over Canberra during the mornings (9am) was southerly, around 26% of the time, compared to the average of 9%. Normally at this time of day and year, the prevailing winds are from the W-NW (34% of the time). In the afternoons, the prevailing wind shifted to become N-NW, with 80% of the observations being observed from this direction, well above the normal frequency of 55% from this direction.

The highest wind gust at Canberra Airport was 78km/hr on the 31st, which was associated with the passage of a front.

Other phenomena

There was plentiful sunshine during the month in the ACT with an average of 9.9 hours per day, the 3rd sunniest October over the last 30 years of sunhine records. The historical average for the month is 8.7 hours per day. The frequency of fog was below average with just the 1 fog reported on the 10th (compared to the average of 3 fogs). There were 3 days when thunderstorms were reported, on the 6th, 13th and 14th with small hail reported at the Airport on the 6th.

Further information

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

Extremes for the ACT

Hottest day
Highest temperature
30.7°C at Canberra Airport on the 27th
Warmest days on average
Highest mean daily maximum temperature
23.1°C at Tuggeranong AWS and Canberra Airport
Coolest days on average
Lowest mean daily maximum temperature

14.0°C at Mount Ginini AWS
23.1°C at Tuggeranong AWS and Canberra Airport

Coldest day
Lowest daily maximum temperature
3.9°C at Mount Ginini AWS on the 22nd
13.8°C at Tuggeranong AWS on the 22nd
Coldest night
Lowest temperature
−4.8°C at Mount Ginini AWS on the 7th and on the 22nd
−0.5°C at Tuggeranong AWS on the 7th
Coolest nights on average
Lowest mean daily minimum temperature
3.6°C at Mount Ginini AWS
6.9°C at Tuggeranong AWS
Warmest nights on average
Highest mean daily minimum temperature
7.2°C at Canberra Airport
Warmest night
Highest daily minimum temperature
16.8°C at Canberra Airport on the 3rd
Wettest overall
Highest total rainfall
39.4 mm at Hall (Lochleigh) (NSW/ACT border)
37.2 mm at Tuggeranong AWS
Driest overall
Lowest total rainfall
16.8 mm at Watson (Racecourse)
Wettest day
Highest daily rainfall
21.2 mm at Hall (Lochleigh) on the 14th
Highest wind gust
78 km/h at Canberra Airport on the 31st

Records

Nil recorded


Summaries for the ACT

Summary statistics for October 2008
Maximum temperatures
for October
(°C)
Minimum temperatures
for October
(°C)
Rainfall
for October
(millimetres)
Mean for
October
2008
Diff
from
normal
Highest for
October
2008
Mean for
October
2008
Diff
from
normal
Lowest for
October
2008
Total for
October
2008
Normal
for
October
Rank of
October
2008
Fraction of
October
normal
Canberra Airport 23.0 +3.6 30.7 27th 7.2 +1.2 0.3 7th 33.2 62.3 low 53%
Mount Ginini AWS* 14.0 20.0 28th 3.6 −4.8 7th 36.0
Tuggeranong** 23.1 +2.5 29.7 27th 6.9 +0.7 −0.5 7th 37.2 49.5 low 75%

** short record, 1996 - 2008 only

* new station, no historic averages available


Notes

This statement has been prepared based on information available at 11 am on Tuesday 4th November, 2008 and updated 11th November. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Averages: historic rainfall and temperature averages are based on all available data.

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