It falls in a part of Portugal (and Europe) that is affected by extreme rainfall, obtaining precipitation levels of 3200 millimetres per year on higher altitudes, and 1600 millimetres at lower altitudes, with more than 130 rainy days per year. Average daily high temperatures range from 10 °C to 21 °C, with some variation; the high lands have an average high temperature of about 11 °C, ranging from 4 to 20 °C, one of the few places in Portugal with an oceanic climate, while areas in the valleys (such as the Homem, Lima and Cávado river valleys) have warmer climates, with daily max temperatures ranging from 12 to 28 °C (with an average of 20 °C), transitioning into a Hot-summer Mediterranean climate. Consequently, the area is prone to various micro-climates, affected by variations in altitude, topographic characteristics, human occupation, different exposures and thermal variation. Similarly, this difference has resulted in an interchange of vegetation characteristic of Mediterranean, Euro-Siberian and Alpine environments. Biome Rivas-Martinez defined the foothills of both the Serra do Gerês and the Serra da Cabreira (lands below the Tâmega, Ave and Cávado watersheds) as the frontier between the Euro-Siberian and Mediterranean regions, granting a significant floral and phytogeographic importance to the National Park. Flora Biomass coverage of the Serra do Gerês, Serra Amarela, Serra do Peneda and Serra do Soajo, as well as the Mourela and Castro Laboreiro plateaus, are dominated by four distinct biomes: oak forest, shrubbery, marshes and riparian vegetation. The floristic diversity includes 823 vascular taxa that occur in 128 types of natural vegetation. The oak forests which are common throughout the park, are especially concentrated in the Ramiscal, Peneda, Gerês and Beredo river valleys. These forested areas are dominated by an alliance between the Pyrenean (Quercus pyrenaica) and European (Quercus robur) oaks, which themselves are differentiated among the lower altitudes and exposed flanks (the Rusceto-Quercetum roboris) and those of typical Atlantic environments (Myretillo-Quercetum roboris). The first association is commonly found with European oak (Quercus rober), cork oak (Quercus suber), butcher's broom (Ruscus aculeatus), maple (Acer pseudoplatanus) and Portuguese laurel (Prunus lusitanica), while the second association unites the European and Pyrenean oaks with bilberry (Vaccinium myrtillus), strawberry tree (Arbutus unedo) and European holly (Ilex aquifolium). In upper altitudes there are patches of European oak that enter into their own association (Holco-Quercetum pyrenacia), which is integrated into another group (Quericon robri-patraea). These oaks have been, over