You can see from the map on top what the area of the mission encompasses. It is a VERY small portion of Argentina — just look at the blue border on the bottom picture.
ABOUT BUENOS AIRES
People from Buenos Aires are referred to as porteños (people of the port). Buenos Aires is a top tourist destination, and is known for its European style architecture and rich cultural life, with the highest concentration of theatres in the world.
Buenos Aires has a humid subtropical climate, with humid summers and mild winters. The warmest month is January, with a daily average of 25.1 °C (77.2 °F). Most days see temperatures in the 28 to 31 °C (82 to 88 °F) with nights between 16 to 21 °C (61 to 70 °F). Spring (September to November) and autumn (March to May) are generally mild and volatile, with averages temperatures of around 17 °C (63 °F) and frequent thunderstorms, especially during the spring.
Winters are temperate, though suburban areas often experience frost from May to September, as opposed to downtown Buenos Aires, which experiences the phenomenon only several times per season. Relative humidity averages in the upper 70%, which means the city is noted for its moderate to heavy fogs during autumn and winter.
The last snowfall occurred on 9 July 2007 when, during the coldest winter in Argentina in almost thirty years, severe snowfalls and blizzards hit the country. It was the first major snowfall in the city in 89 years.
Spring is very windy and variable: there may be heat waves with temperatures of 35 °C (95 °F) even in early October, as well as periods of much colder weather with highs close to 10 °C (50 °F). Frost has been recorded as late as early November, although this is unusual. Severe thunderstorms are likely between September and December.
The city receives 1,242.6 mm (49 in) of rainfall per year. Rain can be expected at any time of year and hailstorms are not unusual.
MORMON HISTORY IN ARGENTINA
Two Latter-day Saint families emigrated from Germany to Argentina in about 1923. They began sharing their beliefs through local newspapers and wrote letters to the First Presidency requesting missionaries. Church Apostle Melvin J. Ballard was sent to Argentina in December 1925 and six people were baptized. The South American Mission was created. Elder Ballard later prophesied that "the work will go forth slowly just as the oak grows from an acorn...[But] the South American Mission will become a power in the Church."
Argentina initially was part of the Church's South America Mission. Then, in 1936, that mission was divided into the Brazilian and Argentine missions. Membership grew slowly for the first 20 years, in 1945 membership in Argentina was 800. The Argentine Mission was divided in 1962, and additional missions have been created since then. In 1998 there were ten missions in Argentina.
The first stake (diocese) in Argentina was organized in Buenos Aires in 1966 with Angel Abrea, now a member of the First Quorum of the Seventy, as stake president. By 1978, membership had reached about 40,000 members. The Buenos Aires Argentina Temple was announced in 1980 and dedicated January 17, 1986.
Buenos Aires was designated area presidency headquarters of the South America South Area in 1984. Three new missions in 1990--Mendoza, Resistencia, and Trelew, and the Buenos Aires West Mission in 1992--reflect the continuing growth in Argentina.
Approximately 4,000 of the Church's 3.5 million South American members live in Argentina. There are 10 missions in Argentina, more than 800 congregations and over 100 Family History sites.
There is one LDS temple in the mission — the Buenos Aires Temple.