Every month is a commonly used phrase to indicate a regular frequency of an event. However, there are several synonyms that can be used instead of every month to add variation to your writing. Some of the synonyms for every month include monthly, each month, per month, every thirty days, every four weeks, and on a monthly basis. These synonyms can be used interchangeably depending on the context of the sentence and the writing style. Using synonyms can also help to make your writing more interesting and engaging for the reader by avoiding repetitive phrases and creating variation.