<strong>Objective:</strong> The objectives were to understand the relationship between humidity and COVID-19 fatality and to provide clues for improving COVID-19 patient survival rate. <strong>Methods:</strong> Humidity data and confirmed COVID-19 death cases for all fifty US states and Washington DC were collected and analyzed, and the relationship between humidity and COVID-19 mortality was derived. <strong>Results:</strong> There is a positive correlation between humidity and COVID-19 patient fatality.<strong> Conclusion:</strong> COVID-19 mortality directly and positively correlates with the humidity of the environment the COVID-19 virus experiences. Such correlation could be used to reduce COVID-19 patient fatality and save lives.