For Hungary and Lake Balaton region, the climate is continental. Parts of Hungary are also in a kind of transition zone between humid and mild climate and continental climate. As a result, there are on average more sunny days and average hours of sunshine per day.
In summer it is warmer here than in Germany (if you look at the average). There could ever be cold in winter with up to -25 °C.

From May to September there is good weather and depending on the weather conditions, you can also swim in lake Balaton from may.
Some spas are open year round and you should try it if you have bad weather or during cold autumn/winter days.

In the last years, some events were also often held in the winter months at Lake Balaton. For example, the Ice Festival Balatonföldvár.