Temperature can be defined as the intensity of heat or cold in a place. A thermometer is used to measure and give readings on temperature. Temperature can be measured using many systems. e.g. Kelvin (K), Celsius (C), Fahrenheit (F).   °F = (1.8 X °C ) + 32° °C = (°F / 1.8) - 32° Conversion table for Celsius, Fahrenheit and Kelvin Humidity can be defined as the amount of moisture in the air. A hygrometer is used to measure the amount of moisture in the air. Humidity can be measured absolutely or relatively. Relative humidity is measured in percent (%). If the air is humid little evaporation occurs as air can only hold up to a certain amount of moisture, while if the air is dry more evaporation occurs as there is a lot more of space for the water to evaporate. Temperature also is a key factor in evaporation. The higher the temperature (more heat, therefore more energy) the higher the rate of evaporation. The colder it is (less heat, therefore less energy) the lower the rate of evaporation. Evaporation of water and condensation of the vapour at certain levels create clouds.