<p>It is commonly assumed that climate change has and will continue to undermine food security in low- and middle-income countries. While substantial evidence supports this expectation, few studies have tested the hypothesis that adverse local climate exposures, particularly high temperatures, directly increase household experiences of hunger or food insecurity. We test this hypothesis using three waves of nationally-representative, longitudinal household survey data from rural Ethiopia, high-resolution climate data, and fixed effects regression approaches. Critically, we examine five food security outcomes and 13 supplementary outcomes, decompose climate effects by season of exposure, and allow these effects to vary across farm size, a relevant measure of vulnerability in the Ethiopian context. Our analysis reveals that both hot and dry conditions during the main growing season, as well as cold and wet conditions during the main harvest season, undermine food security and this is particularly true for smallholder households. The growing season effects are consistent with observed effects on agricultural yields, and the harvest season effects are consistent with observed migration responses. Taken together, the results support the expectation that rural households in Ethiopia are vulnerable to adverse climatic conditions, but do not support assumptions of a uniform decline in food security under climate change, particularly in highland regions.</p>