As spacious as it is, Poland doesn't have much in the way of dramatic climate variations from place to place. What varies most is the weather itself, from day to day and season to season. The country isn't quite as mercurial as Russia when it comes to temperatures, but Polish weather can surprise a visitor at any time of year. Though summer days are typically warm and nights pleasantly cool, a few times each summer the temperature exceeds 30°C/86°F, or drops below 10°C/50°F. Thunderstorms roam Poland from May to August: be prepared for at least one good storm during a week-long visit, and beware of possible flooding if the rains become persistent. The Baltic coast leans more toward showers than thunderstorms, and temperatures hang closer to the 16–20°C/60–68°F range. The Carpathians and Sudeten can experience plenty of thunder and sharp temperature swings.
Autumn is often a golden time across Poland, including the forested south and the Carpathian foothills. Rainfall slackens in autumn – except along the Baltic, where it's often drizzly in autumn – and most nights stay above freezing until November, with many dry, mild afternoons. By winter it's turned cloudy and cold (sometimes bitterly), with light snow falling on as many as half the days. The ground is usually snow-covered through January and February across the north and east. Even on the Baltic coast, the precipitation is often snow (but rarely heavy). Some coastal winters are more blustery than others. A few winter days have been known to climb above 10°C/50°F, especially across the south, as dry, fohn-type winds flow over the mountains and descend. Like autumn, spring is one of the drier seasons across Poland, with more than a few crystal-clear days, even along the Baltic. Temperature gyrations are at their most extreme in spring; you might encounter shirtsleeve warmth or below-freezing chill.