If the earth did not have atmosphere would its average temperature be higher or lower than it is now ?

Question

$\begin{array}{1 1} \text{with out atmosphere , the temperature would be much higher} \\ \text{with out atmosphere , there would be no green hours effect } \\ \text{with out atmosphere , the temperature would not charge} \\ \text{with out atmosphere , the earth will have hotter day colder nights} \end{array} $