Water meniscus formation at the point of contact between an AFM tip and an atomically smooth NaCl substrate was experimentally studied as a function of atmospheric water content, from 70% relative humidity to ultrahigh vacuum (UHV). Meniscus formation was probed by measuring the pull-off point and evaluating the ability of the meniscus to dissolve the NaCl near the point-of-contact as a function of atmospheric water content. Hydrophilic and hydrophobic tips were studied, and although. a decrease in meniscus size was observed for the hydrophobic tips, all data are consistent with both types of tips resulting in the formation of a meniscus even at 0% relative humidity.