Poland has a continental climate with warm summers and cold winters. There is no single best time to visit — it depends what you're after.
Spring (March–May)
Spring is one of the better times to visit the cities. Temperatures climb from cool to warm (7–18°C by May), crowds are manageable, and the countryside turns green. Easter brings festive atmosphere and traditional celebrations, but note that many shops close on Good Friday and Easter Monday. Late April and May are particularly pleasant.
Summer (June–August)
Summer is peak season. Cities are busy, accommodation prices rise, and Krakow's main square can feel overwhelmed on weekends. That said, summer is the best time for outdoor Poland — hiking in the Tatras, sailing the Mazury lake district, or swimming on the Baltic coast. Gdynia and Sopot are lively beach destinations in July and August. Major music festivals run throughout summer.
Autumn (September–October)
Autumn is arguably the best time for city travel. Temperatures are pleasant (13–20°C in September), crowds thin after mid-August, and the cities are at their most relaxed. Foliage in the mountains and forests is spectacular in October. Shoulder season prices apply.
Winter (November–February)
Polish winters are cold — Warsaw averages around 0°C in January, though it can go much lower. Cities look beautiful in snow and are much less crowded. Krakow's Christmas market is one of Central Europe's best. Zakopane and the Tatras are a skiing destination from December through March. Prices for accommodation drop significantly outside the Christmas and New Year period.
The main thing to avoid is a long weekend in summer in Krakow without booking accommodation ahead — the city fills up.