Personally I have to make a monthly calendar and newsletter for the residents and families every month. So I sit down at the beginning of each month and plan out the next month! So by the beginning of June I had July already planned.
This gives me time to book entertainment (this has been easier with COVID since it has to be virtual), and look up monthly observances that I can plan my events around (https://nationaldaycalendar.com/).
Even though most people plan out things way in advance, you will find that every day will be different and may not always go as planned. Because of this fact I know many Activity Directors who print out a daily sheet that says the activities. This way your residents are alerted every day if something on the monthly calendar has changed!
In-House Ice Cream Truck