Despite increasing attention being paid to the temporal dynamics of childhood disadvantage, children's neighborhood characteristics are often measured at a single point in time. Whether such cross-sectional measures serve as reliable proxies for children's long-run neighborhood conditions depends on the stability in children's neighborhood experiences over time. We investigate the temporal stability in children's neighborhood environment, focusing on two of the most commonly studied neighborhood characteristics: The ethnic composition and mean income of the neighborhood. Using Dutch population register data, we follow an entire cohort of children from birth up until age 15. We use year-to-year correlations in the percentage non-Western minorities and the mean income in the neighborhood to evaluate the temporal stability of children's neighborhood experiences. Children's neighborhood characteristics were found to be more stable over time with regard to ethnic composition than with regard to income. Children who had moved at least once were found to have lower stability in neighborhood characteristics than children who never moved. Finally, neighborhood experiences were found to be more stable over time for ethnic minorities than for the native Dutch, although differences were small with regard to income. Single point-in-time measurements of neighborhood characteristics are reasonable proxies for the long-run ethnic composition of children's neighborhood environment, but rather noisy proxies for the long-run income status of their neighborhood, particularly for those who moved.