This paper examines how extreme heat affects consumer sentiment in the banking sector. Analyzing data on complaints filed with the Consumer Financial Protection Bureau (CFPB), we find that extreme heat in consumers' locations leads to increased complaints against banks operating in those locations. The increase in financial consumer complaints is linked to reduced market share and lower non-interest income for banks. The robustness of the results is confirmed through a difference-in-differences analysis using unexpected heat waves as exogenous shocks. The impact of extreme heat on financial consumer complaints varies depending on the sensitivity of consumers to weather conditions, the potential operational deficiencies of banks, and the type of financial product involved. Overall, our study highlights the significant role of heat-induced sentiment in shaping consumer complaints and offers important implications for banks.