Fair weather condition concerns the electric field and the electric current in the air as well as the conductivity of the atmosphere. It is the electrostatic longitudinal modes and electromagnetic transverse mode or state of different meteorological conditions, concerning measurements of atmospheric electrical and meteorological parameters. Fair weather have as component parts an expansive stability range during natural fluctuations.
Around June 1752, Ben Franklin reportedly performed his famous kite experiment. L. G. Lemonnier (1752) reproduced Franklin's experiment with an aerial, but substituted the ground wire with some dust particles (testing attraction). He went on to document the fair weather condition, the clear-day electrification of the atmosphere, and the diurnal variation of the atmosphere's electricity. G. Beccaria (1775) confirmed Lemonnier's diurnal variation data and determined that the atmosphere's charge polarity was positive in fair weather. H. B. Saussure (1779) recorded data relating to a conductor's induced charge in the atmosphere. Saussure's instrument (which contained two small spheres suspended in parallel with two thin wires) was a precursor to the electrometer. Saussure found that the fair weather condition had an annual variation. Saussure found that there was a variation with height, as well. In 1785, C. A. Coulomb discovered the conductivity of air. His discovery was contrary to the prevailing thought at the time that the atmospheric gases were insulators (which they are to some extent, or at least not very good conductors when not ionized). His research was unfortunately completely ignored. P. Erman (1804) theorized that the Earth was negatively charged. J. C. A. Peltier (1842) tested and confirmed Erman's idea. Lord Kelvin (1860s) proposed that atmospheric positive charges explained the fair weather condition and, later, recognized the existence of atmospheric electric fields.