Soil-water evaporation is connected with thermal and moisture regimes in agro-ecosystems and effects land-atmosphere water exchange in the terrestrial hydrological cycle. An inability to measure soil-water evaporation in situ has limited the characterization of evaporative processes. This, in turn, limits understanding of soil-water evaporation for both soil management and large-scale climate modeling. Recent improvements in fine-scale measurement of soil thermal properties provide a new opportunity to address this shortcoming. In these experiments we used three-needle heat-pulse sensors to monitor near-surface soil heat capacity, thermal conductivity, temperature, and water content during natural wetting/drying cycles under open plant canopy conditions. From these data we calculated soil heat flux and changes in heat storage to obtain a balance of soil sensible heat components. The residual from this calculation (i.e., the net heat flux minus the change in heat storage) was attributed to latent heat from water evaporation, and thus, provided an estimate of in situ water evaporation. Results revealed shifting inter-diurnal and diurnal evaporation patterns. The evaporation zone proceeded below 3 mm in the profile within 2-3 d of rainfall events, and thereafter a diffuse evaporation zone continued to extend deeper into the soil with drying. Peak evaporation rates as high as 0.42 mm h^-1 were observed near midday, with evaporation rates declining by late afternoon. Daily heat-balance evaporation estimates taken >2 d after rainfall compared well with microlysimeters, providing root mean square error of 0.11 mm d^-1 and r² = 0.90.