If the Excel Date Filter is not grouping by month, enable grouping dates in the AutoFilter menu, set dates in the proper format, etc.

How to Change Date Format in a Google Spreadsheet. Google spreadsheets, like their Microsoft Excel counterparts, give you the power to tailor data to suit your business needs.

When grouping date values at the query level, you can rely on the DatePart () function. This function evaluates a date value and returns a specific component, so you can use it to group by month ...

It's easy to change the date format in Microsoft Excel. You just need to use the "Date" drop-down menu, which gives you plenty of options.