What is Drought?

The American Association of State Climatologists (AASC) site is a good place to start your search for climatic data in your state, or states, of interest.

U.S. Climate at a Glance, offered by the National Climatic Data Center, provides national, regional, state, and/or local temperature and precipitation maps and data.

NOAA Paleoclimatology Program is the central location for paleoclimate data, research, and education in the field.

What is Paleoclimatology?, from NOAA.

North American Drought: A Paleo Perspective was created by the staff of the NOAA Paleoclimatology Program, with a focus on paleoclimatic data in North America.

North American Drought Variability products from NOAA/NESDIS attempt to provide a clear picture of the full range of drought variability.

Past droughts across the United States are reconstructed here using tree-ring data to complete Palmer Drought Index (PDSI) time series. Check out the history of drought in your region by clicking on the appropriate grid(s). You can then download the data plots for your use.

Map out past droughts by individual years using the PDSI across the United States for either the instrumental era (1895–1995) or from tree-ring reconstructions going back to 1700.

The Laboratory of Tree-Ring Research is located at the University of Arizona.

Science of Dendrochronology Web Pages were designed to be the ultimate source for tree ring information.

United States Interactive Climate Pages from NOAA’s Climate Diagnostics Center include climatologies for cities in the United States, Puerto Rico, and other areas.

CLIMVIS, a great tool from the National Climatic Data Center, historically analyzes the Palmer Drought Index (and its derivatives) by U.S. climate division.

PAGES is a global change program charged with providing a quantitative understanding of the earth’s past climate and environment.

CLIVAR focuses on investigating the processes in the climate system on seasonal, interannual, decadal, and centennial time scales.

The Climate Diagnostics Center provides a nifty historical plotting page for climate divisions in the United States for precipitation and temperature. Choose the time period(s) and parameters you want mapped, and a map will be generated for you. You can build composites and incorporate seasons into the maps as well.

Reconstructing Past Climate in the Southwest is a research project of CLIMAS (Climate Assessment for the Southwest). 

Percent Area of U.S. in Severe to Extreme Drought (1895–2002)

Standardized Precipitation Index