Consider the following premises. Barbara is not drinking water. John is a server if and only if it is snowing. Barbara is a doctor if and only if John is a server. For all y, y is a doctor if and only if y will drink water. Can we infer the following from them? It is not snowing.
 From the fact that for all y, y is a doctor if and only if y will drink water we can infer that Barbara is a doctor if and only if Barbara is drinking water. From the fact that Barbara is a doctor if and only if Barbara is drinking water, and that Barbara is not drinking water we can infer that Barbara is not a doctor. From the fact that Barbara is a doctor if and only if John is a server, and that Barbara is not a doctor we can infer that John is not a server. Finally, from the fact that John is a server if and only if it is snowing, and that John is not a server we can infer that it is not snowing. Therefore, the answer is yes.