Seasonal, tidal, and spring‐vs.‐neap changes in water content, atmospheric exposure, and temperature were studied within the interstices of a porous, semiprotected beach. Semidiurnal tides were nearly equal in amplitude and reached 120 cm from spring low to high. Overall mean grain size was 660 µm and mean sorting, 500 µm, with finer, better sorted, and more layered sand in the upper beach. Pore space averaged 36.5%.Water content at low tide reached minima of 10% pore‐space saturation in shallow sands of the upper beach; most sand above the minimum water table lost >50% of its water. The upper beach drained more completely at neap than at spring tides. Draining occurred more slowly than filling, and deeper sediments drained more slowly than shallow ones, resulting in a progressive landward delay of up to 4 hr in the water table’s “low tide.” Little seasonal variation was noted.Beach temperatures were basically those of the sea surface, modified by duration of exposure. Temperatures of sea and water table followed a gradual cycle of seasonal change, averaging IC/week. Daily temperature variations exceeding 5C were confined to the upper 10 cm of sand in mid‐ and upper beach areas. Neap tides exposed the upper beach for long periods and produced thermal extremes.Salvat’s concept of environmental zones along fine‐sand beaches was modified and applied to both superficial and depth vectors at this coarse‐sand beach.