This data set contains annual freezing and thawing indices for each year from 1901 to 2002 on the 25 km resolution Equal-Area Scalable Earth Grid (EASE-Grid). Annual freezing and thawing indices are defined as the cumulative number of degree-days when air temperatures are below and above 0 degrees C. The values were calculated based upon the monthly mean air temperature from the 1901-2002, 0.5 deg. global land temperatures from the University of East Anglia Climate Research Unit (Mitchell and Jones, 2005). Two ASCII files are available for each year for the freezing and thawing indices, respectively. Each file is approximately 5.5 MB in size. In addition, there is one 10.4 MB ASCII file defining the latitude and longitude coordinates for each grid point. The data set is available in compressed form via FTP.