Climate & Landforms
Hot dry summers and mild winters characterise the climate of the area. The summer average daily maximum temperature is 34 degrees, with a daily minimum of 17 degrees Celsius. In winter this becomes the daily maximum with an average minimum of 5 degrees.
The highest temperature recorded is 46.2 and the lowest minus 3.4 degrees Celsius. The average annual rainfall is 328mm usually falling between March and November. There is an average of 170 clear days per year. 70% of Merredin's rain falls during the growing season from May to October. This is vitally important to the success of the agricultrual activities of the area. The total annual rainfall is approximately 1/3 of that received in Perth.
Weather in the region is dominated by a band of high pressure known as the subtropical ridge. The typical position of this ridge changes during the year and the prevailing winds in Merredin change correspondingly from easterly in summer to westerly in winter.
During winter, the frontal systems in the westerly airstream causes the ridge to move northward resulting in rainfall. Individual heavier falls are associated with strong fronts and systems bringing moisture from the tropics.
Undulating slopes interspersed by granite tors describes the Wheatabelt landscape. This creates a mosaic of plant habitats that include open woodland, gravely or sandy heath, extensive salt lakes and the specialised habitats associated with granite outcrops.
Over 960 species of plants have been recorded within a 50 kilometer radius of Merredin. Of these wattles (acacia) are the most common with around 84 species recorded.
There are around 48 species fo eucalypt and about the same number of orchid species. The most conspicuous features of the landscape are the magnificent granite outcrops and the tall stately trees of the woodland. The sandplain and clay soils are well suited to agriculture.