Daymet historical 1980-2003 Daily weather data for US

A real gem - historical 1980-2003 DAILY weather data for US - extrapolated on 1 sq km grid. Available as summary maps or RAW!
Daymet Home Page:
You can download the raw data for any place in US and use it in research - probability, crop modeling, etc.

DAYMET U.S. Data Center - A source for Daily Surface Weather Data and Climatological Summaries
Daymet is a model that generates daily surfaces of temperature, precipitation, humidity, and radiation over large regions of complex terrain. Daymet was developed at the University of Montana, Numerical Terradynamic Simulation Group (NTSG), to fulfill the need for fine resolution, daily meteorological and climatological data necessary for plant growth model inputs
Using a digital elevation model and daily observations of minimum and maximum temperatures and precipitation from ground-based meteorological stations, an 18 year daily data set (1980 - 1997) of temperature, precipication, humidity and radiation has been produced as a continuous surface at a 1 km resolution. A wide range of summary and point daily data over the conterminous United States are now available.
No other data at this temporal and spatial resolution exists. This data is currently being distributed, free of charge, from the NTSG lab through its outreach component, the EOS Training Center Natural Resource Project.
The Daymet U.S. database is indexed by the Oak Ridge National Laboratory, Distributed Active Archive Center (ORNL DAAC), in their list of Regional and Global Data for Global Change Research