# EXPRESSIONS OF TEMPERATURE

TEMPERATURE refers to the measure of the degree of hotness or coldness of the atmosphere over a given place OR It is the amount of sensible heat or cold with in the atmosphere of a given area.

The major source of heat affecting the atmosphere and the earth’s surface is solar radiation which is defined as the heat emitted and transferred to the earth’s surface by the sun.

However, heat is also transferred from the earth’s surface into the atmosphere which is known as Terrestrial radiation.

The temperature of a place is measured using a sixth thermometer which records the maximum and minimum temperature of the day.

When the highest and lowest temperature is obtained, the following expressions can be made:

## Daily Temperature

It refers to the actual amount of heat or cold that is recorded at a weather station in a day

## Mean Daily Temperature

It refers to the average of heat or cold that is recorded in a specific area in a day. ,It is obtained by;

Mean Daily Temperature = (Maximum Temperature + Minimum Temperature)/2

## Daily (Diurnal) Temperature Range

It refers to the difference between the highest and lowest temperature of the day

Daily Temperature Range = Highest Temperature – Lowest Temperature

## Mean Monthly Temperature

It is the average temperature of an area obtained when the sum of the mean daily temperature for a month is divided by the number of days in the month

Mean Monthly Temperature = Sum of the Mean Daily Temperature
Number of days in a month

## Mean Annual Temperature

It is the final figure obtained when the sum of the mean monthly temperatures in a year is divided by 12 months
Mean Annual Temperature = (Sum of Mean Monthly Temperature)/12

## Annual Temperature Range

It is the difference between the highest and lowest mean monthly temperature in a year

OR It is the difference between the hottest month and the coolest month of the year

## Importance of temperature

Temperature is an important factor in rain formation. Temperature causes the evaporation of water vapour from water bodies, land, and plants. The resulting water vapour then condenses to make clouds that form rain.

Temperature is the main factor in the creation of wind. When the sun heats the earth’s surface unevenly, the resulting changes in temperature create changes in pressure and density. The ultimate result of these changes is the movement of air from a region of high pressure (cold
area) to an area of low pressure (heated area). This movement of air is called wind.

Plant growth and development are also highly influenced by temperature. It affects transpiration, seed germination, and the rate of photosynthesis in different ways.

Temperature controls planting dates and the growth of plants as well as insect pests and crop diseases. As an integral part of the weather, temperature also determines the type of precipitation that might occur if you are in a location that is experiencing near freezing.