The gypsy mothLymantria dispar,like many other forest defoliator species, exhibits periodic population outbreak dynamics, whose variability in different years and in different places can be attributed to different microclimatic parameters. This study was focused on the correlation between climatic variations in two different localities of Sardinia over a three‐year period and on changes in sensitivity of the male antennal olfactory receptors. Our electrophysiological results show that olfactory EAG responses to the sex pheromone of the antennae are inversely correlated with rainfall during gypsy moth larval development. On the other hand, male antennal sensitivity and ambient temperature were not correlated, possibly due to the fact that no significant climatic variations were detected in the period examined. Our findings, especially for rainfall, are in good agreement with data in the literature concerning the effects of weather on gypsy moth population dynamics.