  We study the limit of a local average of the KPZ equation in dimension $d=2$
with general initial data in the subcritical regime. Our result shows that a
proper spatial averaging of the KPZ equation converges in distribution to the
sum of the solution to a deterministic KPZ equation and a Gaussian random
variable that depends solely on the scale of averaging. This shows a unique
mesoscopic averaging phenomenon that is only present in dimension two. Our work
is inspired by the recent findings by Chatterjee \cite{chatterjee2021weak}.
