Can I monitor one station for a period of time, then switch to another?

Yes.

You are allowed to change stations monitored once per month. So, if you decide you no longer need to monitor Station A, you can delete that station and add Station B in its place. But any change locks all choices for 30 days. So be sure to think about exactly what stations you will want to monitor for the next month.

For details on how to select and change stations, see the FAQ on that topic.