Enter a date into an empty, unformatted cell in your Microsoft Excel worksheet. The cell contents must include a month and four-digit year, with or without a specific day.

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 Convert 5-Digit Julian Dates to Regular Dates in Excel. The Julian date format is a five digit number broken into two parts: a two-digit representation of the year followed by a three-digit ...