After beating your Regice, look for the following CP values. These values are those of a Regice with perfect IV's.
Regice has 179 attack, 356 defense, and 160 stamina. As a Raid Boss, it has a CP of 3087.
Regice is an Ice-type. It has access to the following moves:
other viable counters
IMAGE CREDIT: The Pokémon Company