There's always soaking as a new pond fills. Dry soils wick water, so don't be alarmed, yet. Evaporation rates during hot summer months in your area might approach an inch every three days.
Evaporation is a function of humidity as well as temperature. I have seen as much water disappear from a pond in winter sometimes as summer, when humidity is low.
It's probably not evaporation as much as wicking. Stay alert, not necessarily alarmed.

Teach a man to grow fish...
He can teach to catch fish...