A comparison is made between weight increments at 0–3, 4–6, 7–9, and 10–12 months of life between infants born in the fall, winter, spring, and summer seasons in Sui Lin, Taiwan. The focus of the study is on (1) whether in a tropical region the effects of seasonality on weight gain interact with the developmental stage of the infant and (2) whether these interactions are partly regulated by the growth history of the infant. The main hypothesis is that the highest growth velocities will occur in the dry, cold months of the year (fall and winter) and the lowest velocities will occur in the hot, rainy months (spring and summer). The highest and lowest mean birth weights were recorded in the spring and summer seasons, respectively. Season had no effect on weight gain during 0–3 months; on the other hand, birth weight and length were significantly related to weight gain during this 0–3 month period. In the last two seasons of the first year, the highest weight increments occurred in the fall and the lowest occurred in the spring and summer. At the end of the 12 months of life there were no weight differences between cohorts.