A friend recently told me about georgiaweather.net.

The Georgia Automated Environmental Monitoring Network was established in 1991 by the College of Agricultural and Environmental Sciences of the University of Georgia. The objective of the AEMN is to collect reliable weather information for agricultural and environmental applications. Each station monitors air temperature, relative humidity, rainfall, solar radiation, wind speed, wind direction, soil temperature at 2, 4, and 8 inch depths, atmospheric pressure, and soil moisture every 1 second. Data are summarized at 15 minute intervals and at midnight a daily summary is calculated. A microcomputer at the Georgia Experiment Station initiates telephone calls to each station periodically and downloads the recorded data. The data are processed immediately and disseminated via the world wide web.