ACT in July 2011: Dry July with cool nights

  • Below average rainfall.
  • Coldest night since August 1994 on the 29th.
  • Above average maximum temperatures, below average minimums.

Rainfall

Canberra Airport recorded 25.2 mm of rain during July, below the historical average of 40.9 mm. The rain fell over 13 days, slightly above the July average of 11 days, but only one recorded more than 5 mm with 10.4 mm on the 4th. This was associated with the passage of a low pressure trough, with daily falls reaching 29 mm at Tidbinbilla on this day. Total rainfall in the ACT reached 81.1 mm at Tidbinbilla, close to average for July, and 95.8 mm at Mt Ginini AWS.

Temperature

The average maximum temperature at Canberra Airport was 12.3 °C during July, 0.9 °C above the historical average, associated with generally dry conditions during the month and particularly warm days during the final week. Only five days had maximum temperatures below 10 °C during the month, below the historical average of 8 days, with the lowest maximum during the month reaching 7.0 °C on the 24th.

Minimum temperatures were below average during July, at -0.7 °C compared to the historical average of -0.1 °C, associated with dry conditions during the month. All nights during July were cooler than 5 °C, the first time since July 1994, although only seventeen days were below 0 °C, average for July.Nights were particularly cold at the end of the month, with three consecutive nights below -6 °C between the 28th and 30th, the first such period in July since 1971. The coldest night reached -8 °C on the 29th, the coldest July night since -8 °C in 1987 and the coldest night for any month since -8.5 °C was recorded on August 9 1994.

Wind

Canberra Airport was dominated by northwesterly winds during July, with 67% of 3pm winds from a WNW to NNW direction. Two strong wind days were recorded during the month, average for July, with maximum wind gusts of 83 km/hr on the 5th. The strongest wind gust anywhere in the ACT was also on the 5th, reaching 106 km/hr at Mt Ginini.

Other phenomena

No thunderstorms were reported anywhere in the ACT during the month, normal for July. Canberra Airport recorded a daily average of 5.7 sunshine hours, close to the July average of 5.8 hours.

Further information

Media
(03) 9669 4057
Enquiries

Extremes in July 2011
Hottest day 16.6 °C at Canberra Airport on the 3rd
Warmest days on average 12.3 °C at Canberra Airport
Coolest days on average 1.5 °C at Mount Ginini AWS
Coldest day -2.1 °C at Mount Ginini AWS on the 5th
Coldest night -8.2 °C at Tuggeranong (Isabella Plains) AWS on the 29th
Coolest nights on average -2.9 °C at Mount Ginini AWS
Warmest nights on average -0.2 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 7.1 °C at Tuggeranong (Isabella Plains) AWS on the 22nd
Warmest on average overall 6.0 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall -0.7 °C at Mount Ginini AWS
Wettest overall 95.8 mm at Mount Ginini AWS
Wettest day 31.8 mm at Mount Ginini AWS on the 7th
Highest wind gust 106 km/h at Mount Ginini AWS on the 5th


Summary statistics for July 2011
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2011
Diff
from
average
Highest for
July
2011
Mean for
July
2011
Diff
from
average
Lowest for
July
2011
Total for
July
2011
Average
for
July
Rank of
July
2011
Fraction of
July
average
Canberra Airport 12.3 +0.9 16.6 3rd -0.7 -0.6 -8.0 29th 25.2 40.9 low 62%
Mount Ginini AWS 1.5   10.2 1st -2.9   -6.6 15th 95.8
Tuggeranong (Isabella Plains) AWS 12.2   15.9 3rd -0.2   -8.2 29th 37.6

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in ACT Monthly Summary using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 10 am on Monday 1 August 2011. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages 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 20 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average 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, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

Further information

Media
(03) 9669 4057
Enquiries