With annual average rainfall as high as 2700 mm (on average 2200 mm), the Black Forest National Park has one of the highest rates of precipitation in Germany outside of the Alps. It even exceeds the significantly higher-lying southern Black Forest. The reason for this is the Saverne Gap lying to the west. It significantly reduces the rain-shadow effect of the Vosges Mountains meaning that moist air from the Atlantic can practically reach the northern Black Forest without hindrance. Rainfall distribution is relatively uniform throughout the year with maximum rainfall occurring in July. A large part of the precipitation falls as snow an it can cover the ground from mid November onwards. Drifting snow can be common on high ground due to frequent severe storms.
The average annual air temperature in the upland areas is around 5°C, whereas in January the average is -3°C and in July it is close to 13°C. The vegetation period is therefore relatively short. The 10°C mark is exceeded only from June to September. The National Park is often covered with a blanket of fog – 180 days per year according to the statistics. In autumn and winter, however, so-called temperature inversions often occur, meaning that it can be significantly warmer in the upland areas than in the surrounding valleys.