Seasonal weather is somewhat different between the northern and southern regions. In the north there is considerable influence from the Atlantic systems, in which the passage of frequent pressure depressions gives rise to unstable weather conditions. This results in overcast skies and considerable drizzle in the winter.
Rainfall reaches 1,200 mm (47.2 in) a year in some areas. In the summer, excessive heat is rare and temperatures drop noticeably at night. Low temperatures and humidity make for what those living in this part of the country call, optimistically, an "invigorating climate".
In the south, although the rainfall is not significantly low, at around 800 mm (31.5 in), and the winters no milder, the principal difference is in the higher summer temperatures, especially in the Moselle Valley. Crops, especially wine grapes, thrive here. With a mean annual temperature of 10 °C (50 °F), the sunniest months are May to August. In the spring, the countryside is a riot of wildflowers and blossoms.