Attention: NCEI will undergo maintenance on Wednesday, June 3 (6:00 AM - 11:30 AM EDT). Access to many web systems will be unavailable during this time.
The U.S. Historical Climatology Network (USHCN) data are used to quantify national- and regional-scale temperature changes in the contiguous United States (CONUS). The USHCN is a designated subset of the NOAA Cooperative Observer Program (COOP) Network with sites selected according to their spatial coverage, record length, data completeness, and historical stability.