The geographic situation of France determines a wide variety of climatic types. There is an oceanic climate zone, with a low temperature range (mild winter, late spring, relatively cool summer and with average annual rainfall between 800-1000 mm), limited to a narrow strip, to the South, along the Landes, which then it widens N to include the Breton and Cotentin peninsulas and reaches as far as Calais. AE, in correspondence with the Parisian basin, there is a second zone, in which the temperature range is greater and the rainfall is significantly reduced (500-750 mm per year).
Further to the East, between the Morvan and the Argonne, up to the Rhine, there is a gradual transition to climatic types with a continental influence with harsh winters and frequent snowfalls; summers are hot and disturbed by thunderstorms; rainfall is considerable, especially on the hills (Argonne 1200 mm, Morvan 1500 mm, Vosges 1700 mm), while the depressions usually mark minimum rainfall (Colmar 500 mm, Limagne 600 mm).
It is also possible to distinguish an aquitanic climate on the basin of the same name (excluding the coastal strip), peculiar for hot summers, early and rainy springs (but the other drier seasons: annual rainfall 600-800 mm), relatively harsh winters. Finally, the Mediterranean climate prevails with typical warm winters, rainy springs, hot and very dry summers (Languedoc- Roussillon, Lower Provence, Rhone valley as far as Valence); they are the hottest French localities, and with rare rains (600-800 mm per year).
The influence of the relief determines the existence of a real climatic region in correspondence with the Massif Central, rainier than the neighboring districts (averages from 1200 to 1500 mm and more in the Vivarais and Monts Dore mountains) and colder during the winter.
The Alpine system also stands by itself: due to the general orientation of the French Alps from N to S and since the highest altitudes are N, there is considerable diversity between the Savoyard and the Provencal regions; Savoy is much colder with rains (on average, 1200 mm) and more abundant snow, while Provence does not exceed 800 mm of rainfall and is largely affected by the Mediterranean thermal advantages. The same diversity exists between the marginal and central areas of the Pyrenees.
In the northern region the waters meet in three large river basins: that of the Rhine, which collects almost all the waters descending from the Vosges; that of the Seine (with its confluents: Marne, Oise, Eure, Aube, Yonne, Loing), where the waters of the Morvan and Plateau de Langres mountains converge ; and that of the Meuse, corresponding to Lorraine, where the almost lack of tributaries is caused by catches (some in historical age) operated to its disadvantage from the nearby basins. Secondary river routes radiate from the Picardy reliefs: the Scheldt and the Somme. In the Armorican Massif the network hydrographic is independent (Vilaine and Aulne) almost everywhere, albeit with small basins, except to the SE, where the Loire has attracted the waters of Maine and Perche (Mayenne, Sarthe, Loir).
The Loire, the longest French river (1020 km), with a basin of 121,000 km 2, originates from the Massif Central. SW of the Central Massif (Dordogne, Tarn) the Aquitaine basin is partly drained by the Garonne; to the East of the Massif Central, in the large depressed furrow between it and the Alps, the Rhone flows for 2/3 of French territory, with its copious tributary Saone and with the two alpine tributaries Isère and Durance. The southernmost area of the Alpine system is autonomous due to the hydrographic network and the Argens and the Varo descend along very rugged valleys; as well as in the eastern Pyrenees the Aude, the Têt and the Tech flow separate towards the Gulf of Lion.
Climate, soil and vegetation cover make the river regime different from region to region. Seine and Garonne, in particular, are distinguished by a remarkable range in every season. The Seine is a natural waterway from Paris to the sea. A notable feature of the rivers of the Atlantic basin are the estuary mouths, the largest of which are the Gironde (Bordeaux), the Loire (Nantes) and the Seine (Le Havre). The Rhone is also abundant in water, but the steep slopes, in some parts of the course, hinder navigation, as also happens for the Loire. Extensive works were essential to regulate these rivers, with the construction of embankments and connecting canals: among these, the Canal del Centro (Saone-Loire), Dijon(Saone-Seine), those of the Rhône-Rhine, Marne-Rhine, of the East (Saone-Moselle) and of the South (Garonne-Aude).
Flora and fauna
Most of the soil of France is included in the domain of Atlantic flora, with forests of pedunculate oak, beech, hornbeam, elm, chestnut etc., and, especially in the Armorican Massif, with the formation of the moor.
According to allunitconverters, France has the richest and most varied marine fauna in Europe: tuna, sardines, anchovies, coral and sponges are fished in the Mediterranean; cod, sardine and herring in the English Channel and the Atlantic. There are numerous species of freshwater fish: 46 out of a hundred Europeans; some imported from the United States have acclimatized and extended to all regions, such as bluegill and catfish. The terrestrial fauna is relatively rich, possessing more than a third of the Mammals of Europe: only the absolutely southern forms, the typically Nordic ones and the steppe and desert species typical of Eastern Europe are missing.