FYI: Monthly Climate Summary for Canberra - July 2009 [SEC=UNCLASSIFIED]

The following is provided for the information
of subscribers (and as an addition to the annual summary provided in the
Annual Bird Report): http://www.bom.gov.au/climate/current/month/act/summary.shtml

ACT Monthly Summary in July 2009
Dry and sunny July for ACT

·        Below average rainfall
·        Warm days
·        Above average sunshine hours

Rainfall

Canberra Airport recorded a total rainfall of 29.8 mm during July, which is below the 41.2mm average for the month. A total of 11 raindays were recorded during July, which is close to the historical average of 10.5 days. The average amount of rainfall on any day during the month was only 1.0 mm.

The majority of the month's rainfall fell in two main events. The first occured between the 1st and 3rd and the second between the 23rd and 27th. Both of these rain events were caused by the passage of a front and trough over southern NSW and the ACT.

Temperature

Canberra Airport recorded a mean maximum (daytime) temperature of 12.3°C, which is 1.0°C above the average for July. This is now the 11th consecutive July with above average maximum temperatures and ranks equal 12th highest out of 70 years of record. The lowest maximum temperature in the ACT was -1.8°C at Mount Ginini AWS on the 3rd.

Minimum temperatures were slightly above average across the ACT. The average minimum temperature at Canberra Airport was 1.3°C, which is 1.5°C above the historical July average. Frost was observed on 15 days during July, which is below the average of 21.2 days. Average minimum temperatures at Tidbinbilla, to the south west of Canberra, were only 0.2°C above the historical July average.

Temperature extremes in the ACT ranged from a high of 17.2°C at Canberra Airport on the 22nd, to an overnight low of -5.7°C at Mount Ginini on the 6th. This minimum temperature coincided with a high pressure system in The Bight which brought cool air north into the ACT.

Wind

North-westerly winds prevailed during 22% of mornings and 42% of afternoons in the Canberra area, however winds remained relatively calm throughout most of the month. The strongest wind gust of 74 km/h was recorded at Mount Ginini AWS (elev 1760 metres) on the 1st, associated with a cold front moving through central NSW.

Other phenomena

Canberra Airport recorded an average 6.6 hours of daily sunshine, above the long-term average of 5.8 hours, however slightly above average cloud cover was also recorded during July (4.1 oktas compared to the historical average of 3.9 oktas). This can be accounted for by mixed clear and cloudy conditions throughout the month, caused by the passage of a series of high pressure systems over the territory. Occurences of fog at Canberra Airport were below average, with only 4 fog occurences reported during July, compared to the historical average of 7.5 days. No thunderstorms were recorded during July in the ACT.********************************************************************** IMPORTANT: This e-mail is intended for the use of the addressee and may contain information that is confidential, commercially valuable or subject to legal or parliamentary privilege. If you are not the intended recipient you are notified that any review, re-transmission, disclosure, use or dissemination of this communication is strictly prohibited by several Commonwealth Acts of Parliament. If you have received this communication in error please notify the sender immediately and delete all copies of this transmission together with any attachments. **********************************************************************