The three major climate types in France are oceanic (Atlantic Ocean), continental (eastern border and central) and Mediterranean (Mediterranean Sea). The effect on climate of the angle of incidence of the rays of the Sun is that higher latitudes north and south of the Equator experience a cooler and more variable climate, with generally warm summers and generally colder winters.
The higher the N/S latitude of the landmass from the Equator, the cooler and more widely ranging (from warm to cold) the climate of the latitudinal area. The Equator, at 0 degrees latitude, has an angle of incidence of 90 degrees, with the Sun's rays concentrated in a direct line and a more confined area resulting in a consistently hot climate. France, at a generalized latitude of approximately 41 to 49 degrees N, has an angle of incidence in a broad seasonal range of approximately 105 degrees to 150 degrees. The Sun's rays hit Earth in a diffuse concentration dispersed over a wide area resulting in a cooler and more variable climate, having warm summers and cool to cold winters. Climate characteristics are affected by geographical features, such as oceans and mountains.
France's three climate types, influenced as they are by the Atlantic Ocean, the continental landmass and the Mediterranean Sea, experience interesting variations to the climate explained by latitudinal position alone. The southern Mediterranean region, excluding the mountainous area of the southwest, has little rainfall with gentle winters and hot summers resulting from the effects of the Mediterranean Sea on climate. The continental regions of eastern and central France have plenty of rainfall and warm summers, but not hot like in the southern Mediterranean region, with cold and often snowy winters. The oceanic region is affected by the North Atlantic Drift and has ample rainfall and mild, cool summers. Because of the effect of the North Atlantic Drift, winters are mildly cool but seldom cold. The temperature variations in the oceanic region therefore are in a narrow range. The Mediterranean temperature variations are also in a narrow, though warmer, range. The variations in the continental regions are in a much wider range than the other two.
The University of Nebraska’s Daylight Simulator
Isser Woloch, "France: Climate." Encyclopedia Britannica