Southerly and westerly winds predominate, and the sea moderates the climate through onshore winds and the effect of the over the flat country, though the hills in the south significantly diminish the velocity of the potent wind that prevails along the coast. July temperatures average about 63 °F (17 °C), and those of January average 35 °F (2 °C).Annual rainfall averages about 31 inches (790 mm), with only about 25 clear days per year.After this period, a large area in the north of what is now the Netherlands was left covered by soil often subsequently developed in these areas.If the peat soil was washed away by the sea or dug away by humans (for the production of fuel and salt), lakes were created.Nature reserves have been formed by governmental and private organizations.Well-known reserves include the Naardermeer of Amsterdam, the Hoge Veluwe National Park, and the Oostvaardersplassen in the centre of the country. In fact, research has made plausible the contention that the autochthonous inhabitants of the region were a mixture of pre-Germanic and Germanic population groups who in the course of time had converged on the main deltaic region of western Europe.
Although the population as a whole is “graying” rapidly, with a high percentage over age 65, Amsterdam has remained one of the liveliest centres of international youth culture.
Lakes, marshes, peatland, woods, heaths, and agricultural areas determine the general floral species.
Clay, peat, and sand are important soil factors for the inland vegetation regions.
The largest of these to enter the estuary and about three-fourths of the tidal movement to be maintained, limiting damage to the natural environment in the Eastern Schelde.
In the interest of the commerce of the ports of )—that flow from east to west through the central part of the country.
In 1920 work was begun on the , with a total area of about 650 square miles (1,700 square km), were constructed around a freshwater basin fed by the IJssel and other rivers and linked with the sea by sluices and locks in the barrier dam..