It is disputed what norm, if any, governs assertion. We address this question by looking at assertions of future contingents: statements about the future that are neither metaphysically necessary nor metaphysically impossible. Many philosophers think that future contingents are not truth apt, which together with a Truth Norm or a Knowledge Norm of assertion implies that assertions of these future contingents are systematically infelicitous. In this article, we argue that our practice of asserting future contingents is incompatible with the view that they are not truth apt. We consider a range of norms of assertion and argue that the best explanation of the data is provided by the view that assertion is governed by the Knowledge Norm.