The objective of this study was to investigate the effect of seasonality on nutrient intake in healthy adults from the southernmost metropolitan area of Brazil. The dietary intake (24-hour dietary recall on six different days) in a sample of 162 adults (114 women), aged 20 to 69, was obtained during the year 2007. The nutrient intake was averaged for each season and adjusted for energy intake using the residual method. The effect of season on energy, macro and micro-nutrient intake was investigated based on the Generalized Estimate Equations (GEE) model. There were statistically significant differences between seasons for carbohydrate and total fat intake after controlling for gender, age, education, and interactions. In summer carbohydrate intake was higher than other seasons while the total fat intake was lower. These findings highlight the importance of considering seasonal variations not only for evaluating dietary intake but also nutrition and public health policy recommendations, particularly in adult populations living in temperate regions.