Depending on how close the water is to the surface of the sand and in what quantity the temperature will either be higher or lower. Evaporation could also be used to explain some of our observations. After it has rained there are several possible scenarios. One thing that happens is that the rain will run off into the ocean. As this water runs over the sand it will continue to cool the sand until the sand begins to dry.
Evaporation also occurs in which water vapors are released into the air.
This results in the cooling of the sand in all areas again until the sand dries out and evaporation is no longer needed to such an extreme. Transient groundwater is the water that manages to get into the ground and is not released through evaporation. This underground water causes the sand temperatures to remain cool due to the heavy supply of water below the surface. What contribute to the temporal variables are the seasonal changes in the tides and sand input and output. The sand in the winter may be colder than the sand in the summer months due to sand distribution.