I work with power plants, refineries, and paper mills all over the world and often need weather data for site characterization and time series analysis. A great source of world wide weather data is the National Climate Data Center's (NCDC) Global Surface Summary of the Day (GSOD), which is kept on the National Oceanographic and Atmospheric Administration (NOAA) server in North Carolina ftp://ftp.ncdc.noaa.gov/pub/data/gsod There are about 30,000 stations. The data is separated by station and year in UNIX tar balls. You must unzip and extract the data by day. I have written several utilities to facilitate this process. One of these utilities will read the tar balls directly and spit out hourly values of baro, Tdb, Twb, Tdp, and RH. It takes some effort, but it's worth it if you need 20 or 30 years of data at a site in order to have a statistically significant sample. Data that I have received from a specific site (such as a power plant) is proprietary, plus I only have this at a few sites--probably not where you need it.