Salzburg has a moderate historic climate, as you can see from the temperature chart below. Its position on the northern edge of the Alps means Salzburg winters can be quite cold.
Salzburg is known for rains called "Schnürlregen" ("rain in strings"), a very heavy rain that comes in strings but is usually (although not always) quickly over.
July and August are the most popular months to visit Salzburg, especially during the popular Salzburg Festival. Summers are warm and quite pleasant, but can be rainly, as you can see from the rainfall chart below. Winters are cold and there can be lots of snow--but it's still a popular time to go to Salzburg.
The chart below shows the historic high and low temperatures in Salzburg, with the average monthly rainfall chart below that.