Across Wales Sea Bottom Temperature Time Series Data dataset https://portal.medin.org.uk/portal/start.php?tpc=007_NRW_DS109760 Temperature loggers have been placed at sites across Special Areas of Conservations (SACs) in Wales to measure the bottom sea temperature. The data is collected continuously but is processed to give the daily mean temperature as well as yearly averages. This data is collected as part of the Across Wales Diving Monitoring Survey. Additional sea temperature recordings are taken at Skomer Marine Conservation Zone but these are covered in a separate metadata entry. Water temperature is also recorded in saline lagoons at Cemlyn and Pickleridge. The data are captured as part of the Across-Wales Diving Survey, designed to gather information on Reef features across the Marine SACs in Wales. Gathering physical data such as temperature, provides context and background information for the condition assessment of each of the reef features monitored. For example, biogenic reefs and many of the species that occur around the reefs in Wales may be sensitive to fluctuations in temperature. The data collected may provide supporting evidence for any recorded changes in species composition on sites, particularly where species are known to be at the edge of their biogeographical range. All information about the sites is in kept the Temperature loggers site location document. 20151231