How are climates classified?

The main factors are seasonal temperature and seasonal precipitation, though some schemes include native vegetation. The average temperature and precipitation for a whole year are not sufficient for an accurate classification. For example, one climate may have a hot, wet summer, and a cold, very dry winter, which average out to the same values as a different climate that receives mild temperatures and light precipitation year round.

Look up the "Köppen climate classification" on Wikipedia for one common system.