Question: When does the south west wind blow in the largest economy in Africa?

full_context: Document 1: Mali: Mali lies in the torrid zone and is among the hottest countries in the world. The thermal equator, which matches the hottest spots year-round on the planet based on the mean daily annual temperature, crosses the country. Most of Mali receives negligible rainfall and droughts are very frequent. Late June to early December is the rainy season in the southernmost area. During this time, flooding of the Niger River is common, creating the Inner Niger Delta. The vast northern desert part of Mali has a hot desert climate (Köppen climate classification (BWh) with long, extremely hot summers and scarce rainfall which decreases northwards. The central area has a hot semi-arid climate (Köppen climate classification (BSh) with very high temperatures year-round, a long, intense dry season and a brief, irregular rainy season. The little southern band possesses a tropical wet and dry climate (Köppen climate classification (Aw) very high temperatures year-round with a dry season and a rainy season.
Document 2: Geography of Nigeria: With the Intertropical Convergence Zone (ITCZ) swinging northward over West Africa from the Southern Hemisphere in April, heavy showers coming from pre-monsoonal convective clouds mainly in the form of squall lines also known as the north easterlies formed mainly as a result of the interactions of the two dominant airmasses in Nigeria known as the Maritime tropical (south westerlies) and the Continental tropical (north easterlies), begins in central Nigeria while the Monsoons from the south atlantic ocean arrives in central Nigeria in July bringing with it high humidity, heavy cloud cover and heavy rainfall which can be daily occurrence lasting till September when the monsoons gradually begin retreating southward to the southern part of Nigeria. Rainfall totals in central Nigeria varies from 1,100 mm (43.3 in) in the lowlands of the river Niger Benue trough to over 2,000 mm (78.7 in) along the south western escarpment of the Jos Plateau.
Document 3: Climate of Pakistan: Western Disturbances mostly occur during the winter months and cause light to moderate showers in southern parts of the country while moderate to heavy showers with heavy snowfall in the northern parts of the country. These westerly waves are robbed of most of the moisture by the time they reach Pakistan. Fog occurs during the winter season and remains for weeks in upper Sindh, central Khyber Pakhtunkhwa and Punjab. Southwest Monsoon occurs in summer from the month of June till September in almost whole Pakistan excluding western Balochistan, FATA, Chitral and Gilgit -- Baltistan. Monsoon rains bring much awaited relief from the scorching summer heat. These monsoon rains are quite heavy by nature and can cause significant flooding, even severe flooding if they interact with westerly waves in the upper parts of the country. Tropical Storms usually form during the summer months from late April till June and then from late September till November. They affect the coastal localities of the country. Dust storms occur during summer months with peak in May and June, They are locally known as Andhi. These dust storms are quite violent. Dust storms during the early summer indicate the arrival of the monsoons while dust storms in the autumn indicate the arrival of winter. Heat waves occur during May and June, especially in southern Punjab, central Balochistan and interior Sindh. Thunderstorms most commonly occur in northern Punjab, Khyber Pakhtunkhwa and Azad Kashmir. Continental air prevails during the period when there is no precipitation in the country.
Document 4: Nigeria: Nigeria is often referred to as the ``Giant of Africa '', owing to its large population and economy. With 186 million inhabitants, Nigeria is the most populous country in Africa and the seventh most populous country in the world. Nigeria has the third - largest youth population in the world, after India and China, with more than 90 million of its population under age 18. The country is viewed as a multinational state as it is inhabited by over 500 ethnic groups, of which the three largest are the Hausa, Igbo and Yoruba; these ethnic groups speak over 500 different languages and are identified with a wide variety of cultures. The official language is English. Nigeria is divided roughly in half between Christians, who live mostly in the southern part of the country, and Muslims, who live mostly in the north. A minority of the population practise religions indigenous to Nigeria, such as those native to the Igbo and Yoruba ethnicities.
Document 5: Climate of Ireland: Rainfall is the most common form of precipitation on the island, and is extremely common throughout Ireland, although some parts of the west coast receive over four times as much rain as the east coast. Rainfall in Ireland normally comes from Atlantic frontal systems which travel northeast over the island, bringing cloud and rain. Most of the eastern half of the country has between 750 and 1,000 mm (29.5 and 39.4 in) of rainfall in the year. Rainfall in the west generally averages between 1,000 and 1,250 mm (39.4 and 49.2 in). In many mountainous districts rainfall exceeds 3,000 mm (118.1 in) per year. The wettest months almost everywhere are December and January. April is the driest month generally, but in many southern parts June is the driest.
Document 6: Japan: Japan is a member of the ASEAN Plus mechanism, UN, the OECD, the G7, the G8, and the G20, and is considered a great power. Its economy is the world's third-largest by nominal GDP and the fourth-largest by purchasing power parity. It is also the world's fourth-largest exporter and fourth-largest importer.
Document 7: Nigeria: Nigeria was ranked 30th in the world in terms of GDP (PPP) in 2012. Nigeria is the United States' largest trading partner in sub-Saharan Africa and supplies a fifth of its oil (11% of oil imports). It has the seventh-largest trade surplus with the US of any country worldwide. Nigeria is the 50th-largest export market for US goods and the 14th-largest exporter of goods to the US. The United States is the country's largest foreign investor. The International Monetary Fund (IMF) projected economic growth of 9% in 2008 and 8.3% in 2009. The IMF further projects an 8% growth in the Nigerian economy in 2011.
Document 8: Geography of Nigeria: Nigeria, like the rest of West Africa and other tropical lands, has only two seasons. These are the dry season and the rainy season. The dry season is accompanied by a dust laden airmass from the Sahara Desert, locally known as Harmattan, or by its main name, The Tropical Continental (CT) airmass, while the rainy season is heavily influenced by an airmass originating from the south atlantic ocean, locally known as the south west wind, or by its main name, The Tropical Maritime (MT) airmass. These two major wind systems in Nigeria are known as the trade winds.
Document 9: Nigeria: As of 2015[update], Nigeria is the world's 20th largest economy, worth more than $500 billion and $1 trillion in terms of nominal GDP and purchasing power parity respectively. It overtook South Africa to become Africa's largest economy in 2014. Also, the debt-to-GDP ratio is only 11 percent, which is 8 percent below the 2012 ratio. Nigeria is considered to be an emerging market by the World Bank; It has been identified as a regional power on the African continent, a middle power in international affairs, and has also been identified as an emerging global power. Nigeria is a member of the MINT group of countries, which are widely seen as the globe's next "BRIC-like" economies. It is also listed among the "Next Eleven" economies set to become among the biggest in the world. Nigeria is a founding member of the Commonwealth of Nations, the African Union, OPEC, and the United Nations amongst other international organisations.
Document 10: List of African countries by GDP (nominal): 2017 Rank Country Nominal GDP ($billions) Nominal GDP per capita (US $) Notes Nigeria 376.284 1,994.235 South Africa 349.299 6,179.870 Egypt 237.037 2,500.772 Algeria 178.287 4,292.272 Angola 124.209 4,407.657 6 Sudan 119.00 1,428.000 7 Morocco 109.824 3,151.145 8 Ethiopia 80.874 872.840 9 Kenya 79.511 1,701.550 10 Tanzania 51.725 1,033.567 11 Ghana 47.032 1,663.190 12 Democratic Republic of the Congo 41.441 478.237 13 Ivory Coast 40.360 1,616.981 14 Tunisia 40.275 3,496.286 15 Cameroon 34.006 1,400.743 16 Libya 31.331 4,858.672 17 Uganda 26.349 699.410 18 Zambia 25.504 1,479.542 19 Zimbabwe 17.491 1,175.723 20 Botswana 17.168 7,876.997 21 Senegal 16.463 1,038.094 22 Mali 15.318 810.771 23 Gabon 15.206 7,971.589 24 Namibia 12.687 5,413.508 25 Mozambique 12.681 429.296 26 Burkina Faso 12.569 663.806 27 Mauritius 12.428 9,794.102 28 Madagascar 11.463 447.558 29 Equatorial Guinea 10.725 12,726.956 30 Chad 9.872 810.163 31 Guinea 9.721 749.463 32 Benin 9.238 830.404 33 Rwanda 9.137 771.702 34 Congo 8.513 1,958.174 35 Niger 8.253 439.997 36 Somalia 7.382 547.32 37 Malawi 6.206 323.740 38 Eritrea 5.813 979.692 39 Mauritania 5.116 1,317.938 40 Togo 4.767 611.133 41 Swaziland 4.491 3,914.821 42 Sierra Leone 3.641 491.448 43 Burundi 3.396 312.463 44 Liberia 3.285 729.292 45 South Sudan 2.870 228.034 46 Lesotho 2.768 1,425.310 47 Djibouti 2.029 1,988.765 48 Central African Republic 1.928 386.806 49 Cape Verde 1.741 3,237.597 50 Seychelles 1.482 15,685.955 51 Guinea - Bissau 1.350 794.107 52 The Gambia 1.009 480.040 53 Comoros 0.652 787.831 54 São Tomé and Príncipe 0.379 1,785.280 -- Total 2,191.104
Document 11: List of African countries by GDP (PPP): Region Rank Country 2015 GDP (PPP) millions of International dollars -- Africa 5,736,700 Nigeria 1,192.00 Egypt 995.97 South Africa 724.01 Algeria 570.64 Morocco 274.53 6 Angola 185.25 7 Sudan 167.42 8 Ethiopia 159.22 9 Tanzania 150.4 10 Kenya 143.05 11 Tunisia 127.21 12 Ghana 113.35 13 Libya 92.88 14 Uganda 79.75 15 Ivory Coast 78.34 16 Cameroon 72.11 17 Zambia 64.65 18 Democratic Republic of the Congo 63.27 19 Botswana 37.16 20 Senegal 36.30 21 Madagascar 35.56 22 Gabon 34.41 23 Chad 33.73 24 Mozambique 32.00 25 Burkina Faso 31.18 26 Mali 29.15 27 Zimbabwe 28.90 28 Republic of the Congo 27.92 29 Equatorial Guinea 25.94 30 Mauritius 24.84 31 Namibia 24.51 32 Benin 21.16 33 Malawi 20.56 34 Rwanda 20.32 35 Niger 18.96 36 Mauritania 16.43 37 Guinea 15.28 38 Swaziland 10.87 39 Togo 10.82 40 Eritrea 7.94 41 Burundi 7.88 42 Somalia 5.90 43 Lesotho 5.78 44 Gambia 3.27 45 Liberia 3.78 46 Cape Verde 3.48 47 Djibouti 3.09 48 Seychelles 2.53 49 Guinea - Bissau 1.94 50 Central African Republic 1.62 51 Comoros 1.21 52 São Tomé and Príncipe 0.66
Document 12: Nigeria: Nigeria is often referred to as the "Giant of Africa", owing to its large population and economy. With approximately 182 million inhabitants, Nigeria is the most populous country in Africa and the seventh most populous country in the world. Nigeria has one of the largest populations of youth in the world. The country is viewed as a multinational state, as it is inhabited by over 500 ethnic groups, of which the three largest are the Hausa, Igbo and Yoruba; these ethnic groups speak over 500 different languages, and are identified with wide variety of cultures. The official language is English. Nigeria is divided roughly in half between Christians, who live mostly in the southern part of the country, and Muslims in the northern part. A minority of the population practise religions indigenous to Nigeria, such as those native to Igbo and Yoruba peoples.
Document 13: Nigeria: Everything in between the far south and the far north is savannah (insignificant tree cover, with grasses and flowers located between trees). Rainfall is more limited, to between 500 and 1,500 millimetres (20 and 60 in) per year. The savannah zone's three categories are Guinean forest-savanna mosaic, Sudan savannah, and Sahel savannah. Guinean forest-savanna mosaic is plains of tall grass interrupted by trees. Sudan savannah is similar but with shorter grasses and shorter trees. Sahel savannah consists of patches of grass and sand, found in the northeast. In the Sahel region, rain is less than 500 millimetres (20 in) per year and the Sahara Desert is encroaching. In the dry north-east corner of the country lies Lake Chad, which Nigeria shares with Niger, Chad and Cameroon.
Document 14: North American Monsoon: The North American monsoon, variously known as the Southwest monsoon, the Mexican monsoon, the New Mexican monsoon, or the Arizona monsoon, is a pattern of pronounced increase in thunderstorms and rainfall over large areas of the southwestern United States and northwestern Mexico, typically occurring between July and mid September. During the monsoon, thunderstorms are fueled by daytime heating and build up during the late afternoon - early evening. Typically, these storms dissipate by late night, and the next day starts out fair, with the cycle repeating daily. The monsoon typically loses its energy by mid-September when drier and cooler conditions are reestablished over the region. Geographically, the North American monsoon precipitation region is centered over the Sierra Madre Occidental in the Mexican states of Sinaloa, Durango, Sonora and Chihuahua.
Document 15: Nigeria: According to the International Organization for Migration, Nigeria witnessed a dramatic increase in remittances sent home from overseas Nigerians, going from USD 2.3 billion in 2004 to 17.9 billion in 2007. The United States accounts for the largest portion of official remittances, followed by the United Kingdom, Italy, Canada, Spain and France. On the African continent, Egypt, Equatorial Guinea, Chad, Libya and South Africa are important source countries of remittance flows to Nigeria, while China is the biggest remittance-sending country in Asia.
ground_truth: April
sub_queries: What is the largest economy in Africa? Answer: Nigeria
when does the south west wind blow in Nigeria Answer: April