Even up here in Toronto there is a chance even in the snow you will see some of the African animals out. Its likely hit and miss what you will get to see but so long as the yard isnt too icy and the temp too cold there is a chance you will see something. Even ostriches have been out during snow storms. All the animals who can go out based on keeper calls can have access to their yards if they want. There are actually far less species that go totally off exhibit during the winter months than you would think. Might be hit and miss but thats what makes winter visits interesting.