Thanks to steady demand of wood biomass consumption in recent years, assortment wood chips takes significant place on fuel market and right now is popular choice for energetic purposes in Slovakia. Usage of wood chips for heating or electricity production also requires need for storage. Storage of biomass, like wood chips, comes with several health risks for employees of affected workplaces. One of the most important factors causing a health hazard to warehouses of wood chips are microscopic fungi, that live in piles of chips. These fungi can cause a variety of illnesses, like pulmonary diseases, allergies, infections and more. When stored in the open area, on state of fungal activity in wood chips piles has substantial impact weather, mostly temperature and rainfall conditions. The aim of this dissertation is to find out, how impact of weather affected condition of wood chips in four different warehouses during one year time period. Research was oriented on changes in species diversity of fungi and their abundance. Another established objective is analysis of biological hazards to humans, which are related with wood chips storing. In analyzed piles of chips we found 16 various species of fungi, while several of them can be harmful for human health. Output of this thesis is graphic and verbal evaluation of weather impact on fungal activity changes in wood chips piles during one year time period. Another output is overview about identified species and genus of microscopic fungi, the possibilities of their harmful effects on human and related diseases.