NCDC
The U.S. National Climatic Data Center (NCDC) "is
the world's largest active archive of weather data. NCDC produces numerous climate
publications and responds to data requests from all over the world."
It is part of the 
National
Oceanic and Atmospheric Administration (NOAA).
See their FAQs on Global
Warming :
http://lwf.ncdc.noaa.gov/oa/climate/
globalwarming.html
(Dec.1999)
