We usually don't prune our garden before the end of February and even then we consult the 2 week forecast. The main idea is to not have very cold nights in the coming weeks. -5C is not a huge problem now and then, but if there is a sustained -10C for weeks, better delay the pruning.

Your zone 5 seems similar to where we are, but in any case, local weather is more important than zones. Observe and interact 😉

Also, be prepared for a regular summer pruning. The spring prune is usually for large modifications of the shade and character of the tree. It's generally a mistake to make a snip-snip-snip micro pruning in spring, because that will lead to a very dense tree in just a few months. So in spring it's about removing larger branches or parts of the tree to stimulate new growth. In summer is about fine tuning.