On our trip to Italy, we came through Sirmione. Of course, you have to visit Lago di Garda when you’re making a trip to northern Italy. As we were so in love with that lake we finally spent most of our trip around Lago di Garda and Sirmione.
This picture shows the Castle of Sirmione which works as an entrance to the peninsula. The weather that you see was the weather that we had for almost all our trips. I can highly recommend you northern Italy in September, as it is not too hot anymore but still sunny mostly all day long.