Extreme Weather Data Links
NOAA Discovery Portal
National Weather Service
Severe Weather Data Inventory
National Data Buoy Center
LTER Network Data Portal
U.S. Department of Energy
Food and Agriculture Organization of the United States
Ocean Biogeographic Information System
European Severe Weather Database
Data Basin - Datasets
Climate Change Knowlege Portal
Nasa - Global Climate Change
US Climate Data
Comparative Climatic Data - United States
IEM "Climodat" Reports
World Weather and Climate Extreme Archive
NASA Earth Observation
Other Raw Data
Data.gov The US Government pledged last year to make all government data available freely online. This site is the first stage and acts as a portal to all sorts of amazing information on everything from climate to crime.
National Cancer Institute
Human Mortality Database
UCI Machine Learning Repository is a dataset specifically pre-processed for machine learning.
Gapminder Compilation of data from sources including the World Health Organization and World Bank covering economic, medical and social statistics from around the world.
World Health Organization offers world hunger, health, and disease statistics.
UNICEF offers statistics on the situation of women and children worldwide.
Healthdata.gov 125 years of US healthcare data including claim-level Medicare data, epidemiology and population statistics.
NASA datasets – http://nssdc.gsfc.nasa.gov/
World Bank Data – http://datacatalog.worldbank.org/