The Measurement Computing USB-502 data logger measures and stores up to 16,382 relative humidity and 16,382 temperature readings over a 0 to 100 percent RH range and a -35 to +80 °C (-31 to +176 °F) temperature range. You can easily set up the logging rate and start time and download the stored data by plugging the module directly into a PC’s USB port and running the purpose-designed software under Windows Vista/XP/2000. You can then graph, print, and export relative humidity, temperature, and dew point (the temperature at which water vapor in the air begins to condense) data to Excel. The data logger features a long-life lithium battery, which lasts for up to a full year.