We report data on small positive and negative atmospheric ion density at 4 m above the ground correlated to meteorological parameters. Between November 1994 and June 1995, we recorded 75,000 measurements continuously using an ionometer located in Arcachon, a resort on the French Atlantic coast. Compared to meteorological parameters, the data show a strong correlation between the passage of active cold fronts and a large rise of ionic density. ¿ 1998 American Geophysical Union