Climate of Salzburg
Salzburg is at the Northern edge of the Alps and has a typical Central European climate with hot summers up to almost 40 degrees Celsius and cold winters down to minus 20 degrees Celsius.
So most of the year Salzburg has moderate weather conditions and should not keep you from planning your trip at pretty much anytime. Summers are warm and pleasant, although rainy days are common. Winters are cold, temperatures hovering just above or below freezing, with plentiful snow.