This chapter deals with the connection between the light-trap collection of insects and the environmental factors that influence the trapping. These factors are as follows: the solar activity and its effects on the Earth (solar activity featured by Q-Index and the 2800 MHz radio flux, ionospheric storms and atmospheric radio noises, the interplanetary magnetic field sector boundaries, UV-B radiation of the Sun and geomagnetic indices), the moon phases and the polarized moonlight, the weather (macrosynoptic weather situations, weather fronts and air masses, weather events, weather elements), and air pollutants. The presented results show that these all modify the volume of captured insects.