Rainfall across the Adelaide region was close to average across the majority of the Adelaide region for the 2011–12 year (Figure C1). The total area-averaged rainfall over the Adelaide region during the 2011–12 year was 569 mm, which is slightly less than the long-term area-averaged rainfall of 576 mm. Runoff generated during the 2011–12 year within the Adelaide region (see 9.4 Runoff to surface water) decreased by about 50 % compared to the 2010–11 year which received a total area-averaged rainfall of 778 mm (see 'Climate overview' of the 2011 Account). As a result, the volume of water in the storages of the Adelaide region decreased during the 2011–12 year (see 1.1 Storages).
Figure C1 Map of annual rainfall deciles for the Adelaide region during the 2011–12 year
Annual rainfall ranged from more than 800 mm in the east of the region and the Adelaide Hills to less than 500 mm in the northwest near Gawler (Figure C2).
Figure C2 Map of total annual rainfall for the Adelaide region during the 2011–12 year
The area-averaged monthly rainfall was generally close to the long-term average for most months of the reporting period (Figure C3). The first five months of the reporting period (July – November) were all below average. June 2012 was the wettest month of the year, with an area-averaged rainfall total over 100 mm.
Figure C3 Graph of total monthly rainfall for the Adelaide region during the 2011-12 year compared with the long-term average and percentiles for the region
Evapotranspiration across the Adelaide region was generally average for the 2011–12 year (Figure C4). Despite very much above average temperatures (see Temperature), evapotranspiration was limited by average rainfall (see Rainfall).
Figure C4 Map of annual evapotranspiration deciles for the Adelaide region during the 2011–12 year
The total area-averaged evapotranspiration over the Adelaide region during the 2011–12 year was 560 mm. Evapotranspiration was highest along the Mount Lofty Ranges ridge in the eastern part of the region and lowest in the lower elevation areas along the western part of the region (Figure C5).
Figure C5 Map of total annual evapotranspiration for the Adelaide region during the 2011–12 year
The entire Adelaide region experienced annual mean temperatures very much above the long-term average during the 2011–12 year (Figure C6).
Figure C6 Map of annual mean temperature deciles for the Adelaide region during the 2011–12 year
Annual mean temperatures across the region were generally between 14 °C and 16 °C in the western half of the region including Adelaide, while in eastern and southern parts mean temperatures were below 14 °C (Figure C7).
Figure C7 Map of annual mean temperature for the Adelaide region during the 2011–12 year
Mean temperatures in the Adelaide region were above the long-term average for eight months of the reporting period (Figure C8). Mean temperatures in both August and November were above the 90th percentile, with August 2011 ranking as the sixth warmest August on record for the region.
Figure C8 Graph of average monthly mean temperature for the Adelaide region during the 2011–12 year compared with the long-term average and percentiles for the region