Wildfires in the United States can be destructive to human life and property. The ability to predict fire danger helps reduce the risks associated with wildfires by keeping firefighters on high alert and allowing better preparedness. In the state of Oklahoma, fire is a common occurrence. By looking at past wildfire records and researching the weather conditions under which they burned, we were able to determine the most important weather conditions affecting wildfire size. We looked at 10 different weather variables and found that minimum relative humidity (r  =  0.98, P  =  0.001), maximum and average wind speed (r  =  0.95, P  =  0.003; r  =  0.95, P  =  0.004, respectively), and precipitation (r  =  0.88, P  =  0.02) were the most important factors relating to wildfire size. Temperature variables did not have significant relationships with wildfire size categories. Additionally, we found that most of the largest wildfires occurred in January and December. This information can be used to adjust and improve current wildfire danger models and predictive abilities. We define conditions under which firefighters should be on high alert with hopes of improving their ability to expediently manage rangeland wildfires.