Air temperature in complex urban terrain can vary. While roads and buildings can lead to higher temperatures in urban landscapes, trees and other green urban infrastructure can provide cooling. Here, we report on microclimatic variation across the LGA of Cumberland Council, New South Wales.

During the summer of 2018/19, more than 1.4 million individual measurements of air temperature were recorded at 97 locations in and around the LGA. These data were used to: (1) generate the first microclimate maps for Cumberland Council, (2) assess the spatio-temporal dynamics of heatwaves in the area and (3) develop a ranking matrix for the microclimate under street trees. An additional 104,000 measurements of air temperature were recorded at nine locations in the LGA of Bayside to contrast summer heat between coastal and landlocked suburbs in the Greater Sydney Basin. Our data analyses revealed that across the LGA hot and extreme air temperatures occurred more frequently (i.e. 41 days >35°C, 19 days >40°C) compared to a nearby official weather station (i.e. 10 days >35°C, 1 day >40°C). Thus, communities living in Cumberland Council are experiencing extreme heat more frequently than previously known.

Summer daytime temperatures, and particularly those measured during heatwaves, were significantly lower across the coastal LGA of the City of Bayside compared to Cumberland. Due to pronounced cooling during the evening, however, mean nighttime temperatures were lower at Cumberland Council LGA. This new understanding of heat across the LGA of Cumberland Council is based on empirical evidence, making results pertinent and applicable. Analyses provided here offer real-world information to better plan, prepare and respond to increasing urban heat in the future.