Tasmanian Monthly Climate Summary: June 2006
Record dry and record cold nights

Monday 3 July, 2006

In Brief

High pressure systems close to Tasmania meant that there was much less rain, and many more cold nights, than is normal for June.

Details

Record dry June in some areas: Rainfall was very low over most of the state during June, with totals below 10 mm common in the Midlands, the East Coast and the Derwent Valley. Several sites in the central north (including Launceston)  and some around Hobart (including Sorell and Mangalore, both with over 100 years of record)  had their driest-ever June and many more had their driest June for several decades.
Hobart's 6.6 mm was almost 50 mm less than normal for June. It was Hobart's second-driest June since observations began in 1882 (the driest was in 1979), and its driest month since November 2003.
There was rain scattered through the month in most areas, but falls were generally light. Apart from some falls in the northwest at the very start of the month, and through the north around the 23rd, most of the heavier rain was confined to the western highlands.

An extended "cold and dry spell": The spell of mostly patchy or light rain and cold temperatures in many areas extends back to about 11 May. The six or so weeks prior to that had been cold but very wet; some places had their wettest or coldest ever April or their coldest ever May. Rainfall totals for the first half of the year are below normal in almost all parts of the state, and especially so in the north and east.

Record cold nights: Minimum (overnight) temperatures were below normal in all but the far southwest, and by up to 2.5 degrees in the central north. Several sites, including Launceston, recorded their coldest-ever June mean daily minimum temperatures, sometimes by a significant margin.
Almost all nights were colder than normal, often by several degrees. Despite may cold mornings, only Wynyard recorded its coldest-ever June night.

Cool, but not cold, days: Most days were cooler than normal, but often by not very much. The first week was quite cold, but a few warmer days scattered through the month helped to balance these. Averaged across the month, maximum (daytime) temperatures were mostly between 0.1 and 0.5 degrees below normal. At just a handful of sites (Strathgordon, Grove, Maatsuyker Island and Ross) mean June maxima were the coldest they had been since 1995.

High pressure systems the cause: Since about mid-May, Tasmania's weather has often been under the influence of strong high pressure systems. These have suppressed the westerly winds and cold fronts that usually bring a great deal of our rain at this time of year. They have also allowed for light winds and clear skies overnight - especially in the north - and so provided the cold and frosty nights. The same highs have been at the heart of one of the coldest and driest Junes in many parts of Australia.

Included in this summary are a table of extremes, some new records, and summaries for sites across Tasmania.

Further information

Note

This statement has been prepared based on information available at 9 am on Monday 3 July 2006 . Although every effort has been made to check them, it is possible that results will change as new information becomes available.

"Normals" are based on all available years of record, which vary widely from site to site . Sites without normals shown do no have sufficient record for them to be calculated reliably.

The "Ranking" indicates about where rainfall this time ranks in the climate record for the site.

Further information