Changing rainfall patterns have created significant additional risks for agriculture in recent decades. This is particularly evident in the southwest Australian “Wheatbelt” region, where a decline in growing season rainfall since ~2000 CE has led to a major decline in crop production and the profitability of the agricultural industry. While this recent rainfall decline in the Wheatbelt region, and southwest Australia more generally, is consistent with modelled climate change scenarios for the region, the significance of this decline in the context of long-term natural climate variability is poorly understood.

Here, we present an updated tree-ring based 500-year (<1550 – 2018 CE) record of growing season (Feb-Oct) rainfall for the eastern Wheatbelt region of western Australia (30-32°S, 117-120°E). This record reveals inter-annual to centennial scale variability of rainfall and allows us to place recent hydroclimatic trends and events in the context of hydroclimatic variability of the last five centuries. The recent decline in autumn-winter rainfall in the eastern Wheatbelt does not appear to be unusual in terms of either magnitude or duration relative to the last 500 years. Our record shows that drought periods of greater magnitude and duration have occurred in the past five centuries, indicating that multi-decadal droughts are likely a common feature of long-term climate variability in the region.

Our findings highlight that instrumental rainfall records for the last century do not capture the full scale of natural hydroclimatic variability and that drought risk in the region is likely higher than previously thought. This new 500-year rainfall record provides improved knowledge of the multi-decadal to centennial-scale variability of hydroclimate to better inform modelling of future climate scenarios and decisions around agricultural risk and water resource management.