Adelaide: Climate and water

  • Total annual rainfall for the 2021-22 year was slightly above average for the first time since 2016-17.
  • Streamflows during the 2021-22 year were low, reflecting the relatively dry conditions over the region.
  • Soil moisture in the root zone (0–1 m depth) was mostly average across the region during the 2021-22 year, with small areas of above-average soil moisture in the far north.

Schematic representation of the Adelaide region. In 2021–22, rainfall was 638 mm, higher than average after for the fourth consecutive year of below average. Streamflow in North Para River in 2021–22 was 4 GL compared to the average value of 70 GL. Soil moisture was below average.

For further information on the region's climate and water conditions during the 2021–22 year scroll down this page or click on the links below:

 

About the region

  • The Adelaide region generally experiences mild winters and warm, dry summers. Most of the rainfall in the region falls from May–September. Rainfall can be unreliable and infrequent during summer (December–February).
  • Streamflow in the region's rivers generally reflects the distribution of rainfall throughout the year. Most of the streamflow and storage inflow occur during the winter months (June–August) and very little streamflow is observed during the dry summer months (December–February).

 

Climate conditions

Rainfall

Figure C1 Annual and monthly rainfall deciles for the Adelaide region during the 2021–22 year 

  • Total area-averaged rainfall for the year was 638 mm, higher than the mean value of 629 mm.
  • Rainfall was average across most of the region, except for the far north-western corner, which experienced above-average rainfall during the 2021-22 year.
  • A low-pressure trough and cold front brought heavy rainfall to the region in mid-July 2021, contributing to the region's wettest July since 2016.
  • Despite rainfall being above average for both October and November, it was the region's eleventh driest spring on record.
  • December 2021 was the region's fourth driest December on record, with the region receiving 9% of the December monthly average.
  • In January 2022, an ex-tropical cyclone and tropical moisture brought heavy rainfall to the region, contributing to the region receiving more than double the January monthly average.
  • Rainfall from February to April 2022 was below average, meanwhile, rainfall during May and June 2022 was above average.
  • More information on Australia's climate and water over the 2021-22 year can be found at: Financial year climate and water report 2021–22.

 

Figure C2 Total monthly rainfall for the Adelaide region during the 2021–22 year compared with the average and percentiles for the region

  • Rainfall in July 2021 and January 2022 were equal to the 90th percentile, with the region recording its wettest July since 2016.
  • December 2021 was the only month to record rainfall below the 10th percentile, with the region recording its fourth driest December.

 

Actual evapotranspiration

Figure C3 Annual and monthly actual evapotranspiration deciles for the Adelaide region during the 2021–22 year

  • Total area-averaged actual evapotranspiration was average to below average during the 2021-22 year, reflecting the dry conditions.
  • During late-winter and early-spring, evapotranspiration was predominantly average to above average, particularly in July 2021, due to increased water availability following high rainfall in July 2021.
  • By the start of summer, evapotranspiration was predominantly below average following the region's fourth driest December and remained average to below average.

 

Soil moisture

Figure C4 Annual and monthly soil moisture deciles for the Adelaide region during the 2021–22 year

  • Soil moisture in the root zone (0–1 m depth) was mostly average across the region during the 2021-22 year, with a small area of above-average soil moisture in the far north.
  • Following low winter rainfall, soil moisture was average to below average for most of the region during early spring.
  • Although there was a increase in soil moisture during November 2021, soil moisture remained predominantly average through to March 2022 due to a lack of significant rainfall events during summer and autumn.
  • Throughout April and May 2022, soil moisture was below average across almost the entire region following low autumn rainfall.
  • By June 2022, soil moisture was average in the southern half of the region and above average in the northern half of the region following above-average rainfall during May and June.
  • More information on soil moisture distribution across the Adelaide region is available in the Australian Water Outlook.

 

Streamflow responses

Map of key gauging stations. North Para River at Yaldara, station number A5050502, is in the northern part of the region near the town of Gawler. Onkaparinga River at Houlgrave, station number A5030504, is in the central part of the region.
Figure C5 Key flow gauging stations along the main rivers within the Adelaide region

  • Onkaparinga River provides the major inflows into Mount Bold Reservoir—the region's largest storage.
  • Flow along the North Para River is unregulated and not influenced by diversions for consumptive use.

 

Figure C6 Total monthly flow for major rivers in the Adelaide region during the 2021–22 year compared with the average and percentiles

  • Annual streamflow in the region's major rivers was below average during the 2021-22 year, reflecting the dry conditions throughout the year. For example, annual streamflow in the North Para River at Yaldara (Station A5050502) was 4,300 ML compared to the annual average of 12,755 ML.
  • Despite heavy rainfall falling across the region during July 2021, it only produced a minor increase in streamflows with the very dry soil moisture conditions across the region soaking up most of the rainfall that occurred.
  • Little-to-no streamflows occurred throughout summer and into early-autumn due to low rainfall during this period. No flows occurred in the North Para River from January to April 2022.

Note: SA Department for Environment and Water reported that data for Station A5030504 were missing from June 2020. The data used here was a combination of stations A5030504 and A5030504AA.1 (with most of the data not validated and some spikes in flows from November 2021 to June 2022).