NIGHT INFRASTRUCTURE IS CLIMATE INFRASTRUCTURE
HOW EXTREME HEAT IS SHIFTING URBAN LIFE TOWARDS DAWN, TWILIGHT AND NIGHT
By Shashi Karunanethy, Andreina Seijas and Dean Magee
Our cities were largely designed around a daytime economy. Public transport peaks in the morning and afternoon. Shops trade most heavily through the middle of the day. Community services, libraries and government offices mostly operate within business hours. Even the way councils think about activation and place management still tends to revolve around conventional daytime movement and activity, rather than the cooler hours of dawn, twilight and night.
One of the most interesting emergent phenomena of the development of the cities and towns in Australia is the primacy of daytime activity. Operational rules have long reinforced this temporal bias, from restrictive trading hours and overtime regulations to pub closing times, public transport schedules, and emergency service coverage, embedding into the fabric of cities a clear preference for daytime movement, trade, and social interaction.
Extreme heat is beginning to challenge that model. When temperatures move beyond 35 ° C, cities operate differently. People still go out, spend money and access services, but they increasingly avoid the hottest parts of the day. Trips are brought forward into the early morning or delayed until temperatures ease, afternoon errands are cancelled, and dining shifts later into the evening. Anyone walking through our capital cities during a 40-degree afternoon has probably already seen this happening. Streets empty as temperatures rise, shopping strips slow down and activity becomes concentrated around the cooler edges of the day.
The shift is now measurable. Our research using anonymised bank transaction data across Melbourne, Sydney and Adelaide found that consumer spending falls by almost 7 per cent on extreme heat days, with the sharpest declines occurring between midday and early evening when temperatures peak and movement through cities becomes uncomfortable. Evening spending remains far more stable.
The significance of these findings extends beyond retail spending. They suggest that households are already reorganising their daily routines around climate conditions. In practical terms, people are using time itself as a coping mechanism. Rather than withdrawing completely from economic and social activity, they are increasingly shifting activity towards the cooler hours of dawn, twilight and night, when cities feel more usable.
CITIES BUILT FOR COOLER CLIMATES Much of the public discussion around climate adaptation still focuses on physical infrastructure. More trees, cooler buildings, shaded streets, water-sensitive design and better energy systems all remain essential. Yet most of these responses still assume cities continue operating according to the same rhythms that shaped twentiethcentury urban planning. The Australian evidence suggests those rhythms are beginning to change.
The data shows that the economic effects of heat are heavily concentrated in the afternoon. Spending declines sharply between 12pm and 6pm, while the cooler bookends of the day( the dawn economy, as well as twilight and evening activity) remain comparatively stable. Even highly air-conditioned environments such as shopping centres experience significant declines in the hotter part of the day, with many avoiding discretionary trips altogether.
VOL 19 NO 2 2026 08 www. edaustralia. com. au