30 degrees Celsius works out to as 86 degrees in Fahrenheit, and the way you calculate it is simple: Just multiply the Celsius temperature by nine, divide the answer by 5 and add 32. In this instance, the equation would be 30 x 9 = 270 / 5 = 54 + 32 = 86.
To do the conversion the other way round and convert Fahrenheit to Celsius, just do the whole thing the other way round, so 86 degrees Fahrenheit would be calculated by deducting 32 from 86 to give you an answer of 54. Then, you need to divide by nine to get an answer of six. Afterwards, multiply by five to get an answer of 30 degrees Celsius.
The system of recording temperatures by using the Fahrenheit method is named after a German physicist called Gabriel Fahrenheit (1686 - 1736). Using this scale, the freezing point of water is 32 degrees and the boiling point is 212 degrees. The Celsius method of measuring temperature is named after a Swedish astronomer, Anders Celsius (1701 - 1744). This scale was designed so the freezing point of water is 0 degrees and the boiling point is 100 degrees, making it a much simpler system to remember. Because there are 100 gradations between the two points, the original term for this way of measuring temperatures was Centigrade because that means a 100 parts.
Interestingly, many people will use a combination of both the Fahrenheit and Celsius methods, usually for dramatic effect. For example it always sounds hotter if your holiday destination was 78 degrees; but absolutely arctic if you are having to deal with winter temperatures of -3 degrees! In addition, whereas the UK commonly uses Celsius in their weather forecasts, Fahrenheit is more frequently used in US broadcasts.