The issue of the connection between solar and thunderstorm activity is not new. The discussion among scientist begun before cosmic era already. The correlations of the ground based registration of the cosmic rays flux and meteorological observations has been performed since the 50’s of the 20th century. The discussed problem is related to the influence of the cosmic rays on formation of the clouds, particularly thunderstorm clouds. The intensity of the cosmic rays flux strongly depends on the density and velocity of the solar wind. The increase of the solar wind flux during high solar activity leads to decrease of galactic cosmic rays flux, but on the other side, the solar activity creates solar cosmic rays. Using data from the ground based lightning detection and location system PERUN and DEMETER satellite we are trying to estimate the connection between the lightning activity in Poland and solar activity during the period of the DEMETER satellite operational activity (2004-2010). The influence of the thunderstorms on the ionosphere and its dependence on the solar activity is also discussed. However, due to the short time interval of the available data (covering only part of the solar cycle - close to minimum activity) our results are not fully conclusive. Nevertheless, during this time interval some strong Coronal Mass Ejections (CME’s) took place and their effect on the appearance of thunderstorms in Poland is also discussed.