The average temperature during the glacial period or ice age is approximately 5 degrees colder than Earth's current temperature or inter-glacial period.
EXPLANATION:
A glacial period gives the period of ice age whose temperature is specified by colder temperatures and glacier advances. Inter-glacial period shows the warm temperature between glacial periods. Earth currently exhibits in this inter-glacial period.
The change in temperature is based upon the amount of heat radiation received by Earth in Northern hemisphere. The inter-glacial period happens when solar radiation is more intense. It has been observed that the glacial periods end abruptly, maybe due to the atmospheric Carbon-dioxide.
