Biebrzański Park Narodowy - w trosce o bagna

Climate

The Biebrza Wetlands lay in the north east region of Poland, known as the "Green Lungs" region. With an exception of the mountains, this area has a reputation for being the coldest region in Poland. Its climate can be characterized as a combination of continental and sub-boreal, these overlapping characteristics are due to the wide marshy areas that condense moisture on a very large scale and the valley`s unique geological formation. Long winters and a short vegetation growth period characterize the Biebrza valley. The average year round temperature is one of the coldest of these type lowlands with the coldest month coming in February and temperatures dropping as low as -5⁰C. Winters can last up to 117 days and with average maximum temperatures below zero. Snow cover can last up to 140 days in the upper basin with a slightly lower longevity in the southern basin. During the spring and fall, a range of 57 to 66 frosty days is average. July is the hottest month in the Biebrza valley with temperatures topping out at 17,8⁰C. The length of the summer ranges from 77 to 85 days, with daytime temperatures averaging 15⁰C. Foggy nights and morning are quite common and can be seen up to 70 days a year and usually twice that in peaty areas of the valley. The cool air of the surrounding uplands flows and touches the warm waters of Biebrza, this is a quick catalyst for condensation of water steam which givens the appearance of ground fog. The uplands surrounding the valley to a greater extent has a higher level of precipitation than the actual valley floor, 600 mm to 510 mm respectively. As with every typical lowland valley, winds are commonly strong and have a west to southwesterly direction. Due to the valleys high humidity wind storms and tornadoes are rare to almost unheard of.