Trade-wind inversion occurrence over Hilo (green) and Lihue (blue), Hawaii. The frequency of occurrence of the trade-wind inversion increased during the 1990s from less than 80% to occurring around 90% of the time. This finding is consistent with current observations of reduced precipitation, especially for the high-elevations in Hawaii. Figure courtesy of Hawaii State Climatologist, Pao-Shin Chu. Data from Cao et al. (2007).