While ocean acidification (OA) has broadly negative effects on a significant number of marine organisms, their responses are highly variable and could be a reflection of local adaptation. Coastal organisms, in particular, routinely experience pH fluctuations greater than the predicted 0.3-0.4 pH unit decrease in mean global pH by 2100 due to significant seasonal, tidal and diel cycles in seawater carbonate chemistry. These fluctuations are expected to increase in their unpredictability, magnitude and frequency as atmospheric CO2 levels continue to rise. Here, we conduct a meta-analysis of the responses to OA for over 100 species of the economically and ecologically important echinoderm and compare the observed vulnerability against long-term oceanographic carbonate chemistry data at the collection location. pH fluctuations are common around the globe with both longer term seasonal trends and short term autocorrelated patterns. The geospatial pattern of predictability varies with upwelling and latitude. In addition to between order differences in OA sensitivity, there was also a negative relationship between organismal OA sensitivity and increasing predictability in the frequency and magnitude of pH fluctuations in the organismal location of origin. Our work suggests that organismal responses to future ocean conditions are limited by both their evolutionary history and current local environmental conditions.