When income buffers extreme weather: Impacts on women's mental health in informal settlements.

Climate change threatens mental health, especially for the more than one billion residents in informal settlements worldwide. Utilizing longitudinal data collected from women in households in two of Nairobi's largest informal settlements, we examined the mental health impacts of extreme weather and moderating effects of income. Eighteen monthly surveys (September 2022-February 2024) captured experiences of heat, cold, drought, heavy rain, and flooding alongside symptoms of anxiety and depression. Heat, cold, and drought were associated with increased anxiety and depression while heavy rain reduced symptoms and flooding showed no significant association. Critically, income moderated the effects of heat and drought. We identified income thresholds at which heat and drought were no longer significantly associated with symptoms of depression and anxiety. While the income thresholds identified may not apply to all informal settlements, the same approach can help other communities develop locally-grounded guidelines for financial planning to reduce climate-related health risks and inequities. For example, women in households earning below KES 11,000 (~US$87) experienced significant mental health burdens during extreme heat while those with higher incomes did not. These findings suggest that financial vulnerability exacerbates climate-related mental health risks in these communities; however, finance-based interventions-such as forecast-based cash transfers, resilience grants, and community-centered employment programs-could buffer the psychological impacts of climate extremes while strengthening adaptation and reducing inequities.