Significance of Temperature in Gibbs Free Energy
Change in the Gibbs free energy ($\Delta$$\ce{G}$) of a reaction at any temperature can be determined by the equation &lt;$$\ce{$\Delta$G = $\Delta$G^0 + RTlnQ_c (Q_p if the reactants and products are gaseous)}$$ Here, $\Delta$$\ce{G^0}$ is the standard Gibbs-free energy change of the reaction which is determined by,$$\ce{$\Delta$G^0 = $\Sigma$a_iG^0_i_{products} - $\Sigma$b_iG^0_i_{reactants}}$$ where $\ce{a_i}$s and $\ce{b_i}$s are proper stoichiometric coefficients. Now, $\ce{G^0}$ of products or reactants are determined by producing 1 mole of ech of them from their corresponding constituting elements in their standard states and at a FIXED TEMPERATURE(generally at $\ce{298.15K}$). So,  $\ce{$\Delta$G^0}$ is determined also at that particular temperature,So, it is independent of Temperature.  But,when we have to calculate $\ce{$\Delta$G}$ for any reaction at any temperature($T$) by the above given relationship , we have to know the temperature of the reaction condition as you can see clearly, $\ce{$\Delta$G}$ is directly  dependent on $\ce T$.That's why, it's important to know the temperature.