This paper presents the first robust causal estimates of the effect of weather on the allocation of children’s time. It uses individual-level data from over 45,000 time-use diaries of children from two nationally representative cohorts of Australian children whose time-use diaries were surveyed biannually over 10 years to measure the time allocation of children and exploits exogenous variations in local weather conditions observed during the random diary dates. Unfavourable weather conditions, as represented by cold or hot temperature or rain, cause children to switch activities from outdoors to indoors, mainly by reducing the time allocated to active pursuits and travel and increasing the time allocated to media. The effects of weather are more pronounced on weekends and are heterogeneous across different population sub-groups. The results also provide some evidence of adaptation, as temperature tends to have greater impact not only in winter months but also in colder regions. The findings are robust to a wide range of sensitivity checks, including controlling for individual fixed effects and using alternative model specifications