Crop production and profitability in Australia is heavily dependent on both the timing and amount of rainfall. Australia’s southern cropping regions, including “The Wheatbelt” of south-western Australia, have experienced a decline in growing season (autumn-winter) rainfall in recent decades relative to the last century. An understanding of the long-term (decadal-scale and longer) dynamics of hydroclimatic variability is critical to determining the significance of such recent trends in Australian precipitation, as well as informing appropriate management of water resources and reducing uncertainty in climate projections, but is currently hindered by the short length of instrumental climate records.

Here, we present a new 350-year record of autumn-winter (Feb-Oct) precipitation for the eastern Wheatbelt region of western Australia (30-32°S, 117-120°E) reconstructed from ring-widths of the native cypress pine, Callitris columellaris. This reconstruction reveals inter-annual to multi-decadal scale variability of rainfall over the last three centuries, showing periods of below-average precipitation of up to two decades and periods of above-average precipitation, which were typically shorter than a decade. This reconstruction, along with an existing 350-year reconstruction of autumn-winter rainfall for the southern Wheatbelt region allows us to place recent hydroclimatic trends and events in the context of hydroclimatic variability of the last three centuries. The recent period of low autumn-winter rainfall in the eastern and southern Wheatbelt does not appear to be unusual in the context of the last 350 years. Our tree-ring records show that ‘drought’ periods of greater magnitude and duration than those recorded in the last century have occurred in the past three centuries, indicating that instrumental records do not capture the full scale of natural hydroclimatic variability in this region.