Why should we use arrays?

Let's consider that we need to store the average temperature of each month of the year of the city that we live in. We could use something like the following to store this information:

var averageTempJan = 31.9;
var averageTempFeb = 35.3;
var averageTempMar = 42.4;
var averageTempApr = 52;
var averageTempMay = 60.8;

However, this is not the best approach. If we store the temperature for only 1 year, we could manage 12 variables. However, what if we need to store the average temperature for more than 1 year? Fortunately, that is why arrays were created, and we can easily represent the same information mentioned earlier as follows:

averageTemp[0] = 31.9;
averageTemp[1] = 35.3;
averageTemp[2] = 42.4;
averageTemp[3] = 52;
averageTemp[4] = 60.8;

We can also represent the averageTemp array graphically: