This scientific paper presents a correlation analysis between grounding resistance and temperature, humidity, pressure, precipitation, snow cover, solar flux by using program STATISTICA 6. We are reporting the results of grounding resistance measurements of two-year period using a 3-point method. The measurements were conducted during selected periods: from March 1 to March 31 in 2010; from July 1 and July 31 in 2010; from October 1 and October 31 in 2010; from January 1 to January 31 in 2011; from March 1 to March 31 in 2011; from July 1 to July 31 in 2011; from October 1 to October 31 in 2011; from January 1 to January 31 in 2012, in Balozhi, Latvia using the 3-point method with ground resistivity tester type M416. The grounding resistance values are considerably unequal during the different season; the results of the measurements of two-year period and experiments that have been done in the laboratory are the evidence of that. The resistance of any grounding system should be periodically checked to ensure that it is within limits. From our point of view the verification process of the grounding system should be carried out more frequently than once a year, but at least four times throughout the year - in winter, spring, summer and autumn time.