Corporate fraud is an important and long-standing topic in the business ethics literature. As an increasingly common natural phenomenon, extreme weather (EW) disrupts business operations and may affect decisions related to corporate ethics. However, to date, there is a lack of theoretical and empirical evidence on how EW affects corporate fraud. On the basis of fraud triangle theory and data from Chinese listed companies from 2011 to 2022, we find that EW significantly promotes corporate fraud, especially in terms of operational fraud, and this finding is verified in a series of robustness analyses. Mechanistic testing shows that EW promotes corporate fraud by increasing executives' pressure to commit fraud, increasing opportunities for fraud, and increasing the tendency to rationalize fraud. In addition, cross-sectional tests show that when CEOs are party members, corporate nationalism is stronger, regional legal sophistication is higher, social trust is greater, and the effect of EW on corporate fraud becomes non-significant. Moreover, we also find that EW is more likely to lead to operational fraud than to information fraud and executive fraud. Overall, our work contributes to the academic debate related to EW and corporate fraud and provides useful insights for preventing corporate fraud and maintaining the order of financial markets.