The best time to visit Poland is between May and October. The beaches are packed during July and August, so if you're hoping for some peace and quiet it's best to go during May/June or September/October. Plus the weather's pleasant at these times of year. If you're heading to the mountains, bear in mind that, whatever time of year, it rains a lot and without warning!
We loved our Polish adventure and cudos go to all of our guides. We thoroughly enjoyed Warsaw Old Town, The Uprising Museum, Lazienki Park, Chopin, our tour of the Royal Castle and Zapiecek pierogi! Maria recommended that we take the high speed train from Warsaw to Krakow and that was easy and fun. In Krakow we enjoyed the city tour, Oscar Schindler's Factory, Zakopane and the National Park there, Auschwitz including Tour of Birkenau, Jasna Gora to see the Black Madonna and finally the salt mine at Wieliczka.