Question: When does the south west wind blow in the country that's called the 'Giant of Africa'?

full_context: Document 1: Yoruba people: The Yoruba people (Yoruba: Ìran Yorùbá, lit. 'Yoruba lineage'; also known as Àwon omo Yorùbá, lit. 'Children of Yoruba', or simply as the Yoruba) are an ethnic group of southwestern and north - central Nigeria, as well as southern and central Benin. Together, these regions are known as Yorubaland. The Yoruba constitute over 40 million people in total. The majority of this population is from Nigeria, and the Yoruba make up 21% of the country's population, according to the CIA World Factbook, making them one of the largest ethnic groups in Africa. The majority of the Yoruba speak the Yoruba language, which is tonal, and is the Niger - Congo language with the largest number of native speakers.
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: Nigeria: Among Christians, the Pew Research survey found that 74% were Protestant, 25% were Catholic, and 1% belonged to other Christian denominations, including a small Orthodox Christian community. In terms of Nigeria's major ethnic groups, the Hausa ethnic group (predominant in the north) was found to be 95% Muslim and 5% Christian, the Yoruba tribe (predominant in the west) was 55% Muslim, 35% Christian and 10% adherents of other religions, while the Igbos (predominant in the east) and the Ijaw (south) were 98% Christian, with 2% practising traditional religions. The middle belt of Nigeria contains the largest number of minority ethnic groups in Nigeria, who were found to be mostly Christians and members of traditional religions, with a small proportion of Muslims.
Document 4: Nigeria: According to a 2001 report from The World Factbook by CIA, about 50% of Nigeria's population is Muslim, 40% are Christians and 10% adhere to local religions. But in some recent report, the Christian population is now sightly larger than the Muslim population. An 18 December 2012 report on religion and public life by the Pew Research Center stated that in 2010, 49.3 percent of Nigeria's population was Christian, 48.8 percent was Muslim, and 1.9 percent were followers of indigenous and other religions, or unaffiliated. Additionally, the 2010s census of Association of Religion Data Archives has reported that 46.5 percent of the total population is Christian, slightly bigger than the Muslim population of 45.5 percent, and that 7.7 percent are members of other religious groups.
Document 5: Namibia: Typically the sub-Tropical High Pressure Belt, with frequent clear skies, provides more than 300 days of sunshine per year. It is situated at the southern edge of the tropics; the Tropic of Capricorn cuts the country about in half. The winter (June – August) is generally dry, both rainy seasons occur in summer, the small rainy season between September and November, the big one between February and April. Humidity is low, and average rainfall varies from almost zero in the coastal desert to more than 600 mm in the Caprivi Strip. Rainfall is however highly variable, and droughts are common. The last[update] bad rainy season with rainfall far below the annual average occurred in summer 2006/07.
Document 6: Nigeria: With the majority of Nigeria's populace in the rural areas, the major languages of communication in the country remain indigenous languages. Some of the largest of these, notably Yoruba and Igbo, have derived standardised languages from a number of different dialects and are widely spoken by those ethnic groups. Nigerian Pidgin English, often known simply as 'Pidgin' or 'Broken' (Broken English), is also a popular lingua franca, though with varying regional influences on dialect and slang. The pidgin English or Nigerian English is widely spoken within the Niger Delta Regions, predominately in Warri, Sapele, Port Harcourt, Agenebode, Ewu, and Benin City.
Document 7: 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 8: 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 9: 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 10: 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 11: 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 12: 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 13: 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 14: Nigeria: Nigeria is a religiously diverse society, with Islam and Christianity being the most widely professed religions. Nigerians are nearly equally divided into Christians and Muslims, with a tiny minority of adherents of Animism and other religions. According to one recent estimate, over 40% of Nigeria's population adheres to Islam (mainly Sunni, other branches are also present). Christianity is practised by 58% of the population (among them 74% are Protestant, 25% Roman Catholic, 1% other Christian). Adherents of Animism and other religions collectively represent 1.4% of the population.
Document 15: 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.
ground_truth: April
sub_queries: Which country is called the 'Giant of Africa'? Answer: Nigeria
when does the south west wind blow in Nigeria Answer: April