Temperature variation within intertidal sands was observed at two stations in Tomales Bay, California. The annual range and seasonal trend temperature at 10 cm beneath the sand surface are similar to those in the open water of the bay. The daily variation resembles that observed in terrestrial soils. Animals living in the upper 1 cm are exposed to a daily temperature range as great as three times that experienced by subtidal individuals of the same species. The animals living at 10 cm or deeper are subject to a temperature regime similar to that of the subtidal environment.