Sand covers a significant portion of the Earth’s surface, including the Grand Falls area of Coconino County, AZ. The vadose zone (unsaturated zone) in a soil is of particular interest because it is broadly applicable to desert soils, which are seldom saturated and usually dry. In the absence of strong geothermal heating, the near-surface soil temperature profile is expected to exhibit maximum variation (for a given diurnal period) at the surface, with the diurnal variations becoming successively damped with depth. The temperature at a given depth is the result of diffusive heat transport vertically within the soil column. Water vapor also is expected to be transported via diffusion through the soil column [1]. We have selected a sand sheet within the Grand Falls Dune Field (GFDF) and deployed temperature and relative humidity sensors at 5 different depths: 1, 6, 12, 24, and 48 cm to capture diurnal temperature and humidity variations. [1] Hillel, D., (1980) Fundamentals of Soil Physics