3rd January 2006

NSW CLIMATE SUMMARY 2005 - NSW REGIONAL OFFICE

NSW 2005: 2nd warmest year on record with drought breaking rains

Annual Temperatures:

In 2005 NSW experienced its warmest year since 1914 with an annual mean temperature 0.98 ºC above average. This is the second highest on record (1.02 ºC above average was recorded in 1914). Mean temperatures (average of maximum and minimum) across NSW were above average to very much above average, except in the southern Riverina, where temperatures were close to average. A large area extending from the north west to the A.C.T. experienced its highest mean temperature on record (see map 1).

Very much above average maximum temperatures were experienced across the majority of the state in 2005 with areas of the Mid North Coast and South Coast experiencing highest mean maximum temperatures on record (see map 2). The annual average maximum temperature for the state was 1.34 ºC above average, ranking as the 4th warmest on record. April was a record warm month for the state with maximum temperatures west of the ranges more than 3 degrees above the historic average. Minimum temperatures were below average in the southern Riverina and above average the remainder of NSW. An area around Cobar in the Upper Western experienced its warmest minimum temperatures on record (see map 3). The annual average minimum temperature was 0.62 ºC above average, ranking as the 8th warmest on record.

TABLE 1: NSW Temperature Extremes For 2005

Annual Rainfall:

Rainfall for 2005 was average or close to average across most of the state, an average of 494mm fell across the state compared to the normal 566mm. Below average falls were recorded in the Illawarra, Sydney Metropolitan, the Upper Western and the northern half of the North West Slopes and Northern Tablelands. Large parts of the Lower Western, Riverina and Central Tablelands received above average annual rainfall (see map 4). NSW experienced two distinct rainfall regimes through the year. The first five months of the year were very dry across almost the entire state with large areas west of the ranges experiencing very much below average falls (see map 5). Large parts of the Upper Western received the lowest rainfall on record for the January to May period. In marked contrast the June to December period was very wet across most of the state with large areas west of the ranges receiving very much above average falls (see map 6). The shift to wetter conditions was marked by incursions of moisture from the tropics interacting with winter cold fronts, leading to the formation of several northwest cloud bands which brought widespread rain to most of NSW. Heavy falls also resulted from a number of upper level cold pools during the winter-spring period.

The wetter than average June to December period has finally relieved drought conditions across much of NSW with the drought affected area falling from 89.3% of the state in July to 18.5% in December (NSW Dept. of Primary Industries http://www.agric.nsw.gov.au/reader/drt-area)

Several stations set new daily rainfall records through the year:

TABLE 2: NSW Daily Rainfall Records For 2005

TABLE 3: NSW Rainfall Extremes For 2005

A note about deciles: Deciles are used to give an element (in this case rainfall and temperature) a ranking. Deciles are calculated by arranging the totals in ascending order (from lowest to highest) then splitting them into 10 equal groups (thus the groups are called deciles). The first group would be in decile range one, the second group in decile range two, etc up to the highest annual totals (highest 10 per cent) being in decile range 10.

Averages: Averages are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation.

Further information: Contact Clinton Rakich 9296 1555, email: reqnsw@bom.gov.au

A directory of Bureau services is available on poll fax: 1800 630 100

For the latest rainfall and temperature maps, see: http://www.bom.gov.au/climate/austmaps/