Heat mapping conducted across the Campbelltown, Cumberland and Parramatta LGAs has revealed temperature variations of more than 10 degrees can occur between individual streets due to variations in size and type of urban canopy and elements of the built environment.

The three studies, led by Dr Sebastian Pfautsch from the Western Sydney University, saw the deployment of over 350 heat sensors across the three LGAs and revealed that the communities of Western Sydney are exposed to extreme heat more frequently than official records indicate.

For example, under this project, heat sensors across the Parramatta LGA indicated maximum air temperatures were greater 35°C on 47 days. For the same period, the BoM weather station at North Parramatta recorded 25 days where air temperatures were greater than 35°C.

Significant differences have also been recorded between official BoM weather stations. Parramatta’s second official station, at Olympic Park, recoded only 10 days over 35°C. This indicates that some members of the community are experiencing far greater temperatures than others, with implications for health, energy bills, and liveability. 

This study also found significant variation in the cooling potential of different tree species. 

“Air temperatures under canopies of different park tree species varied greatly and predictably. During hot days, the coolest air temperatures were recorded under large, densely foliated crowns of Queensland weeping figs, whereas those measured under open crowns of tall eucalypt trees were much hotter. During the night, this trend reversed.”

Across the three LGAs, the study noted systematic trends in the relationship between cooling characteristics of different tree species.

Dr Pfautsch notes that “Additional research is necessary to better understand these relationships that can inform selection processes for landscape plantings and support initiatives that aim to increase resilience against urban heat.”

This research has a number of very practical applications.

1. Benchmarking heat will allow councils to measure the impacts of various cooling strategies and new developments on urban microclimates over time.
2. Mapping local hotspots will allow councils to target cooling investments to the areas of greatest need.
3. With additional research, the project will begin to inform tree species selection for landscape plantings to achieve maximum cooling benefits.
4. The study indicates the need for a review of the way we determine thresholds for the distribution of heat warnings and community outreach.

For further information on this research read the full reports:

Research report: Benchmarking heat in Parramatta, Sydney's Central River City (2019).

Research report: Benchmarking heat across Cumberland Council, New South Wales (2019).

Research report: Benchmarking heat across Campbelltown, New South Wales (2019).