The authors summarize published data on the inorganic chemistry and occurrence of clouds and fogs in the western U.S. Cloudwater chemistry differs among regions (southern CA to coastal AK). Most variability in the data can be attributed to differences in total dissolved ionic concentrations among sites. Ionic concentrations generally decrease from urban/industrial sites in southern CA toward forested sites in more remote, northern areas. Differences in cloudwater chemistry among sites generally appear greater than differences among events at a given site. Samples from southern CA are generally more acidic than those from the more northern sites (mean minimum pHs = 2.52 and 4.48, resp.). Most cloud interception is anticipated along the Pacific coast in the Coast Range of northern CA, OR, and WA and along the western slopes of the Cascades. The available data on cloudwater chemistry indicate that these regions experience clouds of relatively low ionic concentrations, however the limited data should be supplemented to substantiate this result.