The moisture content of a maturing crop varies as harvest season progresses. For crop residues such as corn stover, moisture content at the time of harvest can be as high as 75% (wet mass basis) to less than 20% depending on the geographical location (climate conditions) and the stage of harvest. Moisture content is critical to baling and extended storage of biomass. It is therefore essential to have an accurate estimate of the quantities of corn stover available as wet or dry for various parts of the United States. To this end, we analyzed hourly weather data (temperature, humidity, rainfall) from the Typical Meteorological Year v.3 (TMY3) database developed by National Renewable Energy Laboratory (NREL). A recently published set of equations for calculating the moisture content of stover as a function of hourly temperature, humidity, and rainfall were used. The annual start and end of corn grain harvest, along with the annual grain production (in bushels), for each State within the continent were extracted from United State Department of Agriculture’s (USDA) National Agricultural Statistics Service (NASS) reports. Using these datasets and equations, the percentage of harvest season (in hours) that moisture content of stover was less than 20% or between 20% and 40% or more than 40% was calculated. These calculations were carried out for several locations within each of the States and averages are reported. It was concluded that about 37.2% of corn stover is dry (less than 20% moisture content), while 36.5% is wet (higher than 40% moisture content), nationwide. The remaining 27.0% of corn stover is between 20% and 40% moisture content.