This study aims at examining the impact of spatial resolution and the time lag on the relationship between the rainfall intensities and the cloud-to-ground lightning rate during rainy events that occurred in North of Benin in 2006. The lightning data used of this experiment have been collected by LINET network and the rain data are provided by a network of 23 rain gauges. The results obtained show that the temporal scales between the beginning of the electrical activity and precipitations are optimal when these letters are synchronized. The average optimal radius is identified at 8 km around the rain gauges location. In most cases (59 %), the maximum of electrical activity precedes the maximum of precipitations. The heavy rainfalls to ground are offset in time with regard to a peak of electrical activity with an average of 5 minutes.