Seymour Island or Marambio Island, is an island in the chain of 16 major islands around the tip of the Graham Land on the Antarctic Peninsula. Graham Land is the closest part of Antarctica to South America. It lies within the section of the island chain that resides off the west side of the peninsula's northernmost tip. Within that section, it is separated from Snow Hill Island by Picnic Passage, and sits just east of the larger key, James Ross Island, and its smaller, neighboring island, Vega Island. Seymour Island is sometimes called Marambio Island or Seymour-Marambio Island, taking its resident Argentine base as its namesake (see section, Base Antárctica Marambio, below). Historic site A wooden plaque and rock cairn stand at Penguins Bay, on the southern coast of Seymour Island. The plaque was placed on 10 November 1903 by the crew of the Argentinian Corvette Uruguay on a mission to rescue the members of the Swedish expedition led by Otto Nordenskiöld. The inscription on the plaque, placed where the two parties met, reads: “10.XI.1903 Uruguay (Argentine Navy) in its journey to give assistance to the Swedish Antarctic expedition”. The cairn was erected in January 1990 by Argentina at the site of the plaque in commemoration of the same event. The site has been designated a Historic Site or Monument (HSM 60), following a proposal by Argentina to the Antarctic Treaty Consultative Meeting. Base Antárctica Marambio Located in the island is the Marambio Base which is the main Argentine base in Antarctica operating an airfield (ICAO SAWB) for wheeled landing the whole year. In winter the base has an average of 55 crew members, but in summer the population of the base can grow to 180. Climate The average temperatures on Seymour Island, as measured at Base Antárctica Marambio, are during the summer and during the winter. In the wintertime, however, strong winds can lower the wind chill temperature feeling to as low as on exposed skin. On 9 February 2020, a temperature of was recorded on the island. However, on 1 July 2021, the World Meteorological Organization invalidated the reading because based on the analysis of the data, the air temperature was recorded in non-standard conditions, leading to bias and errors in the temperature sensor and readings. Paleontological significance The rocks making up Seymour Island date mainly from the Late Cretaceous to the Eocene. Successively younger rock formations found