The higher elevation gives the ecoregion a subtropical to temperate climate, in contrast to the dry tropical climate of the lowlands. Rainfall is higher than the lower-elevation dry forests and deserts of the peninsula, averaging 760 mm annually. Rain falls mostly in the summer, with occasional winter rains.
The oak woodlands from 800 to 1200 meters elevation are warmer and drier, with evergreen oaks predominant (principally Quercus devia; Q. arizonica and Q. rugosa have a limited distribution), along with lower trees and shrubs such as Dodonaea viscosa, Bumelia peninsularis, and Buddleia crotonoides.
Above 1200 meters elevation, the oak woodlands transition to oak-pine forests. The only pine present is an endemic subspecies of Mexican Pinyon, Pinus cembroides subsp. lagunae, mixed with oaks, including Quercus devia and Q. tuberculata, and other broadleaf trees, including Arbutus peninsularis and Nolina beldingi. Lower trees and understorey shrubs include Calliandra peninsularis, Mimosa xanti, Heterotoma aurita, Verbesina pustulata and Hypericum peninsulare. Above 1600 meters elevation, pine predominates, mixed with oaks, and with an understory of grasses (Muhlenbergia spp. and Festuca spp.).