The GLOBE program is in a major expansion program in terms of its scientific data gathering efforts at schools around the world. In addition to continually adding nations, schools, teachers and students to its program, GLOBE is adding new scientific protocols and measurements that will debut in 1999. One of these measurements is the noontime relative humidity, which will easily be accomplished while the most commonly available GLOBE measurements being taken to date are already being made. At local noon each day, students make observations of the 24-hour precipitation accumulation, current temperature, and maximum and minimum temperature. These observations already require students to go outside to make their observations. Through a simple procedural change in the order that these observations are made, no significant time will be added to the total observation time. During the first year, we will investigate the type of observation to be made. The two candidates are an aspirated psychrometer (which will provide measurements of air and wet-bulb temperature) and a relative humidity hygrometer. The present expectation is that more reliable data would be available through a psychrometer, while keeping mind that we are searching for the best combination of accuracy and cost (keeping new instruments below $100). Direct relative humidity observations would allow for the easiest method and would be appropriate for students at all levels; use of a psychrometer would force students to use graphs or other means to determine the relative humidity, a worthy goals for students at higher levels (middle to high school). We will discuss the rationale for adding relative humidity to the list of GLOBE science protocols, our methodology for determining the most suitable instrument, and strategies which we hope will lead to interesting curricular applications in any project involving studies of the water balance in the climate system