Sydney
Climate overview
Rainfall
Rainfall across the Sydney region was below average to very much below average for the 2013–14 year (Figure C1). The total area-averaged rainfall over the Sydney region during the 2013–14 year was 646 mm, which is below the long-term area-averaged rainfall of 889 mm (based on the 1900–2014 period).
These conditions represent a decrease in rainfall compared to the 2012–13 year, when rainfall was close to average across most of the region (see the 2013 Account). As a result, there was decreased runoff into the storages during the 2013–14 year (see the Surface water note).
Annual rainfall ranged from more than 900 mm near the southern coastal boundary to less than 600 mm in the central and northern parts of the Sydney region (Figure C2).
Figure C2 Total annual rainfall for the Sydney region during the 2013–14 year
Rainfall was well below average in much of eastern Australia during the 2013–14 year, while rainfall was well above average in parts of southern and northern central Australia and the southeast coast. There were no strong influences from large-scale drivers during the reporting year, with a short-lived negative Indian Ocean Dipole event decaying at the start of the year. The El Niño-Southern Oscillation was neutral for most of the year, although rapid warming of eastern Pacific towards the end of the year caused an El Niño Alert to be issued in April.
The area-averaged monthly rainfall was below the long-term average for most months during the 2013–14 year. August and October 2013 and January 2014 were particularly dry months and all fell below the 10th percentile rainfall. March 2014, which received 171 mm of rain, was the wettest month, close to the 90th percentile.
Figure C3 Total monthly rainfall for the Sydney region during the 2013–14 year compared with the long-term average and percentiles for the region
Evapotranspiration
Potential evapotranspiration across the Sydney region was generally very much above average for the 2013–14 year, with record highs present in small isolated pockets of the region (Figure C4).
Figure C4 Annual evapotranspiration deciles for the Sydney region during the 2013–14 year
The potential evapotranspiration estimate was produced by the Australian Water Resources Assessment system landscape model (AWRA-L) version 3.0 (Van Dijk 2010). The AWRA-L model uses a modified version of the Penman–Monteith method to produce the potential evaporation. Daily AWRA-L potential evaporation grids were produced based on daily gridded climate data that were available on a 0.050 (approximately 5 km) national grid.
The total area-averaged potential evapotranspiration over the Sydney region during the 2013–14 year was 1,210 mm compared with the long-term area-averaged potential evapotranspiration of 1,146 mm (based on the 1970–2014 period). Potential evapotranspiration was variable throughout the region but was highest in small pockets near the coastal boundary (Figure C5).
Figure C5 Annual potential evapotranspiration for the Sydney region during the 2013–14 year
Temperature
The Australian area-averaged mean temperatures were highest on record for the 12–month period ending June 2014. During this same period, most of the Sydney region experienced mean temperatures that were the highest on record or very much above average, based on the 1911–2014 period (Figure C6).
Figure C6 Annual mean temperature deciles for the Sydney region during the 2013–14 year
Annual mean temperatures across the Sydney region ranged from more than 18°C along the coast and approximately within a 50-km radius Sydney, to less than 12°C in isolated areas along the western border (Figure C7).
Figure C7 Map of annual mean temperature for the Sydney region during the 2013–14 year
Monthly mean temperatures for the Sydney region were greater than the long-term average for all months during the 2013–14 year except for November 2013, which was close to average. In particular, temperatures in six months of the reporting year (July–October 2013 and May–June 2014) exceeded the 90th percentile mean monthly temperature, with September 2013 being the warmest September on record at 14.5°C.
