Stuttgart experiences an oceanic climate , just like the British Isles and Northern France, but it is very extreme at times. As a result of the urban heat island caused by the dense development of the city, inside its “Cauldron” average temperatures in the summer months regularly beat 20 °C (68 °F) from June to August and come very near in September. In the winter temperatures are quite mild, with daily means never sinking below 0 °C (32 °F) even in the coldest months (January and February). In spite of the heat, there is no dry season and the city receives frequent but moderate precipitation year-round. Annually, the city receives average 718.7 mm (28.30 in) of rain (German average national annual rainfall is 700 mm (28 in)). On average, Stuttgart enjoys 1,807 hours of sunshine per year and an average annual temperature of 9 °C (48 °F).
Typically during summer months, the nearby hills, Swabian Alb mountains, and Black Forest, Schurwald, and Swabian-Franconian Forest act as a shield from harsh weather but the city can be subject to thunderstorms, whereas in the winter periods snow may last for several days. Winters last from December to March. The coldest month is January with an average temperature of 0 °C (32 °F). Snow cover tends to last no longer than a few days although it has been known to last several weeks at a time as recently as 2010. The summers are warm with an average temperature of 20 °C (68 °F) in the hottest months of July and August. Summers last from May until September. Though it is a rare occurrence in Stuttgart, the city sometimes receives damaging hailstorms, such as in July 2013. In order to fight this phenomenon, weather stations known as “Hagelflieger” are stationed near the city and are largely funded by Daimler AG, who maintain several parking lots and factories in the municipal area.