Concept of Weather

Is the average weather condition of an area recorded over a long period of time (over 30 or 35 years). This involves systematic observation, recording and processing of the various elements of climate such as rainfall, temperature, humidity, air pressure, winds, clouds and sunshine before any standardization of the climatic means.

For example when we say climate of Norway is hot wet equatorial climate that is the summing up of the average everyday weather conditions of the country throughout the year.

1. Good weather improves people's lives
2. Weather determines the kind of clothing to be worn by people in an area.
3. Knowledge of the weather of a place enables people to carry out economic activities, which can be sustained by the weather in that place. E.g. dairy cattle do well in a cool and wet place.
4. By studying the weather of a place over a long time, we can establish its climate.

Most human activities affected by weather that is experienced at a place. For example, when the rains are heavy, flooding occurs and causes damage to crops, animals and infrastructure like roads. This means that few economic activities can take place. When there is no rain, plants and animals die, rivers and streams dry up, and irrigation and other economic activities like fishing cannot be carried out.

There are 7 elements of weather:

1. Sunshine
2. Temperature
3. Humidity
4. Cloud cover
5. Precipitation
6. Wind
7. Atmospheric pressure

1. Sunshine

• This is the sun's rays that reach the surface of the earth.
• The sun's energy enables plants to manufacture food through the process of photosynthesis.
• People need sunshine to dry their crops, food like cassava, millet, maize and fish. They also use sunshine to warm themselves.
• Dries clothes after washing them.

2. Temperature

This is how hot or cold an object or place is. The sun supplies the heat in the atmosphere.

Importance of temperature

• Warmth is essential for plant and animal survival.
• Plants need warmth in order to manufacture their food.
• Facilitates formation of clouds.

3. Humidity

Is the amount of water vapor (moisture) in the atmosphere.

There are two types of humidity

1. Absolute humidity and
2. Relative humidity

Absolute humidity: Is the actual amount of water vapor or moisture in a given volume of air at a particular temperature.

Relative humidity: Is the ratio of the actual amount of water vapor or moisture in a given volume of air (i.e. absolute humidity) to the maximum amount of water vapor that the same volume of air can hold at the same temperature.

4. Cloud

Clouds are masses of tiny droplets of water or ice particles or both which are suspended in the atmosphere. They are formed when water vapor or moisture in the atmosphere cools and condenses.

Importance of cloud: Are important because they condense to form rain and other forms of precipitation.

5. Precipitation

This refers as the fall or deposition of moisture water vapor or frozen water from the atmosphere onto the earth's surface. All life on the earth is purely dependent on moisture provided through precipitation.

Importance of precipitation

1. Rain provides water for plants to grow (i.e. water for irrigation, growth of grass and pasture depend on rain).
2. Animals also need water to drink.
3. Human needs water for domestic and industrial uses.

Note: Excess rain and rainstorms result in disasters due to flooding.

6. Wind

Wind is air in motion. It is made up of variety of gases, such as oxygen and carbon dioxide. Wind move horizontally from areas of high pressure to areas of low pressure.

They cause flow of heat and moisture and their transfer from one point to another and are also responsible for the movement of clouds.

Wind direction and wind speed or velocity is two important aspects in geography.

Wind Direction

Wind direction is important because it helps us understand the characteristics of particular winds in terms of:

1. Temperature: Winds from different directions may bring different temperatures, such as cold winds from polar regions or warm winds from tropical areas.
2. Moisture Content: Wind direction also affects the moisture content of the air. For example, winds from the ocean may bring moist air, while winds from the land are typically dry.

Wind Speed

The velocity of the wind determines its strength or force, which influences weather conditions:

1. Strong winds can have significant effects, such as:
   • Little or no rainfall in some cases.
   • Dry conditions due to the wind's ability to carry moisture away from an area.
2. Weak winds generally result in less noticeable weather changes.

7. Atmospheric Pressure

Atmospheric pressure is the force exerted at a point on the Earth's surface due to the weight of air above that point. The atmosphere is the layer of air surrounding the Earth's surface, and it has mass, which generates pressure.