The given diagram is a scatter plot in which temperature is plotted against number of visitors.
As the number of visitors is rising with the rise in temperature, its a positive correlation.
As joining the dots is going to give a web of line segments, it is not going to be helpful to understand the trends.
The best way to understand the trends is to make the line of best Fit in such a way that the number of dots on either side are approximately the same.
I have attached the figure for your reference of the line of best fit.
