Children often say that strange and improbable events, like eating pickle-flavored ice cream, are impossible. Two experiments explored whether these beliefs are explained by limits in children's causal knowledge. Participants were 423 predominantly White Canadian 4- to 7-year-olds (44% female) tested in 2020-2021. Providing children with causal information about ordinary events did not lead them to affirm that improbable events are possible, and they more often affirmed improbable events after merely learning that a similar event had occurred. However, children were "most" likely to affirm events if they learned "how" similar events happened (OR = 2.16). The findings suggest that knowledge of causal circumstances may only impact children's beliefs about the possibility "after" they are able to draw connections between potential events and known events.