Protecting Health in Extreme Heat: Australian Willingness to Pay for Heat Early Warning Apps

Abstract Heat early warning systems are important to adapt to increasingly frequent periods of extreme heat. Early warning messages, based on weather forecasts and indices reflecting human thermal responses, are increasingly delivered through smartphones. Personal preferences for when and how such warnings should be delivered vary among individuals, reflecting differences in heat perception and tolerance. We assessed personal preferences for heat warning thresholds including 1) the maximum predicted temperature, 2) the number of predicted consecutive hot days, 3) the level of behavioral advice provided with warnings, and 4) the willingness to pay for a heat warning app with the preferred features. Nearly two-thirds of respondents from Australia (63%; n = 2272) are willing to pay AUD $1.89 (95% CI: 1.78–2.00) monthly for an app that issues warnings when maximum temperatures are predicted to exceed 38°C for 2–3 consecutive days. Latent class analysis identified three distinct groups that differ in their preferred trigger temperature and heat duration thresholds: “self-reliant adapters” (42% of all respondents), “young information seekers” (35%), and “risk-aware pragmatists” (23%). All groups preferred detailed behavioral advice on how to cope with heat as a feature of the warning message. Willingness to pay was positively associated with age, perceived threat, and coping capacity. The findings provide behavioral insights to guide the design and targeting of digital heat warning messages in Australia. A personalized subscription-based heat warning app with enhanced features could complement existing free services and accommodate the diverse preferences identified across population groups. Significance Statement Very hot days and long periods of extreme heat can make people feel unwell and, in severe cases, cause death. As heat waves become more frequent with climate change, it is increasingly important to warn people early so they can take action to stay safe. Smartphone apps can deliver such warnings directly, but people differ in when they want to receive them and what kind of advice they find helpful. This study asked more than 2000 Australians about their preferences for heat warning messages on their smartphones. Most (63%) were willing to pay a small amount per month for warnings sent when very high temperatures are predicted for several days and that provides clear, personalized advice on how to cope. Older people and those who felt more at risk from heat were especially supportive. This suggests demand for enhanced services that could complement, rather than replace, free universal warnings through existing channels. The results can also guide the design of heat warning systems to be more effective and user-focused.