the highest average annual air temperatures of the United Kingdom. In common with much of the south Cornish coast, summer daily maxima rarely exceed about 25 degrees Celsius (77°F) and below freezing temperatures and frost are uncommon. The lower valley and beach enjoy a micro-climate being sheltered from winds in most directions. For the more exposed cliff-top areas, gale-force winds are common throughout the year which occasionally cause moderate structural damage to buildings locally. In the summer months Porthcurno is popular with families on holiday with young children who enjoy playing on the beach and perhaps some supervised bathing, as the beach is prone to strong rip currents. In the quieter seasons visitors tend to be local people and day-trippers from other parts of Cornwall. Many tourists come from elsewhere in the United Kingdom and abroad and may have rented self-catering or bed and breakfast accommodation nearby. The Porthcurno Telegraph Museum and the Minack Theatre, both bring visitors to the area. History Porthkornow, Porthcornow The name Porthcurno evolved from the 16th century Cornish spelling 'Porth Cornowe'. In the Cornish language '' (standard written form uses "c") meant 'cove/landing place of horns or pinnacles', a reference to the granite rock formations in the vicinity. Some evidence of early commercial port activity exists in the remains of man-made stone tracks for horse-drawn vehicles which may have provided access to the beach, visible on one of the footpaths near the south side of the car park ascending the east side of the valley. Industrial and wartime developments Development of the area was dominated for over one hundred years by the operations of the cable station owned by Cable and Wireless plc and its predecessor companies. Probably over 90% of the inhabitants were either employees of Cable and Wireless or were directly supported by it. During the Second World War, Porthcurno was designated a Vulnerable Point and was heavily defended and fortified as a part of British anti-invasion preparations. At the beginning of the war a small guard of special constables was put on duty at the cable office and cable house, later superseded by a platoon of soldiers who camped on a former bowling green. Porthcurno valley was declared a protected place and as many as 300 troops were deployed in the immediate area to guard the station. Passes were issued to residents and visitors who had business to be in the area