The study compares the hazel pollen seasons in Szczecin, Drawsko Pomorskie, Bydgoszcz, Zielona Gora, Wroclaw, Opole, Sosnowiec, Cracow, Piotrkow Trybunalski, Warsaw, Lublin, Olsztyn and Bialystok in 2018. The investigations were carried out using the volumetric method. The hazel pollen season began between 24th January and 7th March. Maximum daily pollen concentrations were noted earliest on 3rd March and latest on 4th April. The greatest risk of allergies caused by the presence of airborne hazel pollen was observed in Lublin. Based on phenological observations of hazel pollen emission, it was found that pollen release also occurred on frosty days with high sunshine hours.